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М.Х. НАРМУРАТОВА1, А. БАЙДУЛЛАЕВА1, А.Е. МУРАТБЕКОВА1,
ДМ. МЭЗБАЕВА1, Ж.Б. НАРМУРАТОВА12* 1эл-Фараби атындагы ^азак улттык университетi, Алматы, ^азакстан 2Satbayev University, Алматы, ^азакстан *e-mail: [email protected]
КОРОНАВИРУС ЦОЗДЫРГЫШЫНА ЦАРСЫ ИММУНОМОДУЛИЯЦИЯЛЬЩ АГЕНТ РЕТ1НДЕ CYT ЛАКТОФЕРРИН1НЩ ЦАСИЕТ1Н СИПАТТАУ
doi: 10.53729/MV-AS.2023.01.03
ТYЙiн
Б^л макалада, КЪтайдыц орталык каласы Уханьдагы пациенттерде ерекше вирустык пневмонияныц пайда болуына экелш соктыратын жаца коронавирустыц пайда болуы COV-тыц (2019-nCoV) денсаулыкка кауштшп туралы жарияланды. Ка^рп COVID-19 пандемиясы барысында, вируска карсы кептеген тагамдык коспалар непзвде аурумен кYресуге жэне алдын алуга назар аударылуда. Лактоферрин (ЛФ) - CYткоректiлердщ CYтiнде кездесетш табиги тагамдык коспалардыц бiрi жэне темiрдi байланыстыру кабiлетi мен кептеген жасуша рецепторларымен байланысу негiзiнде иммуномодуляциялык касиеттерге ие. Лактоферриннщ вируска карсы кабшет SARS-CoV-2-мен (COVID-19 коздыргышы) тыгыз байланысты SARS-CoV жэне баска да вирустарга карсы багаланды. Сонымен катар, лактоферрин кабынуга карсы тиiмдiлiкке ие. Лактоферриннщ SARS-CoV-2-ге карсы потенциалына арналган арнайы зерттеу ж^мыстарын жYргiзу ете кажет, ейткенi Лактоферриннщ вируска карсы иммунитетке катысты биологиялык белсендiлiгiне байланысты SARS-CoV-2 жасушаларын ж^ктырудыц алдын алады немесе кедергi келтiруi мYмкiн. Лактоферриннщ SARS-CoV-2-ге карсы фармакологиялык эсерiн багалау бойынша келесi зерттеулер оныц COVID-19-пен кYресудегi релiн керсетедi деп Yмiттенемiз.
Кiлттi сездер: лактоферрин, SARS-CoV-2, COVID-19, иммуномодуляция.
Вирус - генетикалык материал мен б1рнеше акуыздан к^ралган дене. Т1р1 агзага ену аркылы кебеюге кабшетп, ауру тудырушы агент. Коронавирус (CoV) - Virus патшалыгыныц Coronaviridae т^кымдасына жататын, corona (тэж) жэне viridae (вирус) сездершщ б1р1гушен к^ралган вирус тYрi. CoV - адам, yü жанарлары, к^с, жарганат, тышканныц жэне баска да кептеген жабайы жануарлардыц тыныс алу жолдарын, асказан-1шек, бауыр жэне орталык жYЙке жYЙелерiн закымдайды [1-3]. Ауыр жедел респираторлык синдром (АЖРС) немесе SARS (SARS - Severe acute respiratory syndrome) жукпалы жэне ел1мге экелу1 мYмкiн респираторлык ауру. SARS - коронавирустыц инфекциясыныц нэтижеа, оны галымдар SARS-мен байланысты коронавирус (SARS-CoV) деп атады. 20022003 жылдары SARS немесе АЖРС ауруы 5 континенттеп 33 елге таралып, нэтижесшде 8000-нан астам адам инфекция ж^ктырып, 700 адам кайтыс болган [4-6], ал 2012 жылы Таяу Шыгыста респираторлык синдромнан (MERS - Middle East respiratory syndrome) 2428-ден астам адам жуктырып, 838 адам кайтыс болып, катац бакылауга алынды. Аталган шдеттщ ершу1 секшд1, жацадан пайда болган CoV-та жануарлардан - адамга жэне адамнан-адамга жылдам таралу мYмкiндiгi жагынан катерл1 шдет болгандыгын керсетп [7-8]. 2019 жылы, желтоксан айыныц ортасында орталык ^ытайда орналаскан Хубэй
провинциясына юретш Ухань каласыныц Хуанань жануар мен тещз ешмдер1 базарында болган халык т^ргындары белпаз пневмонияныц ершу1 бYкiл элемнщ назарын аудартты. ^ытайдыц гылыми зертханаларында катац реттшк пен этиологиялык зерттеулер жYргiзу нэтижесшде, белпаз пневмонияныц коздыргышы ретшде - жаца коронавирус (novel Coronavirus (nCoV)) аныкталды (http://virological.org/ жэне https://www.gisaid.org/). Осыдан кешн, ^ытай галымдары коронавирустыц жаца тYрiн - SARS-CoV-2 деп атады. Оныц генетикалык к¥рылымы ауыр жiтi респираторлы синдромды коздыратын SARS-CoV
вирусына 70% уксайтыны аныкталган. 2020 жылдьщ 12 кацтарында ДYниежYзiлiк денсаулык сактау уйымы уакытша жаца вирусты 2019 жылдыц жаца коронавирусы (2019 -nCoV) деп атады [9]. SARS-CoV-2-нiц негiзгi таралу жолы заттардыц сырткы бетi аркылы таралуы мYмкiн, атап айтканда, ауруды жуктырган адам жетелгенде немесе ауруды жуктырган адамды устаган дене мYшещзбен бепщзд^ кездерщзд^ мурныцызды укалаган сэтте жYзеге асады [10]. Алайда, вирустыц ол жерлерде канша уакыт емiр CYретiндiгi белгiсiз. Осылайша, вирус агзага енiп, кебейедi жэне баска мYшелерге таралады. Негiзгi закымдаушы нысандары: iшек, кекбауыр жэне ец кауiптi эсер ететiн мYшесi екпе. Вирусты жуктырган адамдарда кургак жетел, температураныц жогарылауы, ентiгу, екi жакты пневмония жэне баска да белгшер, соныц iшiнде, тамак ауруы, диарея мен кусудыц жещл жэне ауыр клиникалык керiнiстерi байкалады [10]. Ауырган наукастар инфекция жуктырган адамдармен жэне тыныс алу тамшыларымен тыгыз байланыста болуы мYмкiн [11]. Вируска карсы кептеген емдеу эдiстерi усынылган. Алайда, адамдарга сынак жYргiзу кезещ бiрнеше айга немесе бiр жылга созылуы мYмкiн [12]. Пандемиямен ^ресудщ казiргi эдiсi - окшаулану, жеке гигиена шаралары жэне дурыс тамактану.
CoV-тыц жаца тYрлерiнiц пайда болуы мен ершу^ денсаулыкка кауiптi жаhандык катерлi iндет болып табылатындыгын керсеттi. Болашакта, климат пен экологияныц езгеруiне жэне адамныц жануарлармен карым-катынасыныц кYшеюiне байланысты кауiптi iндет жацадан ершуi мYмкiн. Осылайша, жедел терапия мен CoV - га карсы вакциналар жасау кажеттшп туындады. Элемдiк пандемияга айналдырган коронавирустык жаца iндеттiц алдын алу жэне одан коргануга макалада келтсршген мэлiметтер ез септiгiн тигiзедi деп Yмiттемiз.
Коронавирустыц жасушага ену жолы. Коронавирустыц адам жасушасына енуi келесщей этаптардан турады. 1. Адамныц мурын, ауыз немесе кез мYшелерiмен кемегiмен агзага енген вирус ангиотензин конвертеушi фермент 2 (АСЕ2) акуыз - рецепторына карай багытталады (сурет 1). АСЕ2 - металлопептидаза, SARS-CoV-2 Yшiн мацызды функционалды рецепторлардыц бiрi. Ангиотензин конвертеушi фермент 2 рецепторы кейбiр мYшелердiц курамына кiретiн жасушалардыц бетiнде орналасады, атап айтканда, ауыз куысы мен мурынныц шырышты кабаты, екпе, асказан, аш iшек, ток шек, лимфа тYЙiндерi, айырша без, CYЙек кемiгi, бауыр, кек бауыр, бYЙрек жэне мидыц курамында болатын жасушаларда кездеседi. АСЕ2 рецепторы екпе альвеолыныц эпителий жасушаларыныц бетiнде ете кеп болады [13].
SARS-CoV- 1 гпч г: н.п1- Спайн акуызы (S)-rinACE! ацуыэ-рецеоторымем байланысуы
Вирустыц жасушэга Kipyi, АСЕ2-н1ц дурыс
КЫЗМеТШ|Ц буЭЫЛуы
Сурет 1 - Коронавирус жасушасы мен оньщ АСЕ2 рецепторымен байланысуы бейнеленген [27]
Eipmmi cypeire GeMHeneHreHgeM, KopoHaBHpyc BHpycw aHrHoTeH3HH KOHBepTeymi ^epMeHT 2 pe^nTopbiH :acyma GeTiHeH TaHbiFaHHaH KeMiH, aTanFaH pe^nTop MeH CnaMK a^yw3w (S) «KmT» neH «K^nbin» ceKingi Gip-GipiMeH GepiK GaMnaHbicagbi. KpHcTannorpa^Hflnbi; 3epTTeynepge KepceTinreHgeM, K¥paMbrnga S1 cerMeHT (318-510 aMHH KbimKbin KangbiKTapw) aHrHoTeH3HH KOHBepTeymi ^epMeHT 2 pe^nTopw YmiH MaRbi3gbi pe^nTopnapMeH GaMnaHbicaTbiH aMMa; [13-15]. EepiK GaMnaHbic aceprneH ;aH ^hchmhh peTTeyre KaTbicaTbiH ACE2 pe^nTopbiHbiR ;bi3MeTi G:pbMagbi. H3TH:ecmge, aHraoTeroHH KOHBepTeymi ^epMeHT 2 pe^nTopw KeMeriMeH SARS-CoV-2 BHpycw agaM aF3acbiHbiR :acymacbiHa eHegi [16]. ^acyma imiHe eHreHHeH KeMiH, KopoHaBHpyc BHpycw cbipTKbi ;opman T^praH Gapnbi; K^pbinbiMgbiK a;yw3 KaGaTbiHaH GocaMgbi [15]. ^orapwga KenripinreH peniniKneH, SARS-CoV-2 e3i HeMece TeK reHoMgbi; PHK цнтoпnaзмaFa eHegi. An, SARS-CoV BHpycbiHbiR PH^ reHOMw ¥3biHgbiFbi maMaMeH 30000 HyKneoTHgTi K¥paMgbi [17]. BupycTHR :acyFa eHyimR Keneci caTbicbiHga, цнтoпnaзмaFa eHreH BHpyc, PH^ a;yw3WHa :ayanTbi aKyw3gapgwH TpaHcn^H^cbi Ke3e«i Gacranagbi. ^Tonna3MaFa eHreH reHoMgbi; PHK peпnнкaцнfl npo^ci Heri3rnge eKi eceneHy пpoцeci :ypegi. PH^ peпnнкaцнacwн :Y3ere acwpMac G^pwH SARS-CoV-2-;a PHK peпnнкaцнflCbIн :y3ere acbipaTbiH Ma«bi3gbi a;ybi3gap ;a:eT. ATanFaH aKybi3gapgbi BHpycTbi; PH^-Hbi MaTepHan Ke3i peTiHge naMganaHbm TY3inyi TpaHcn^HA gen aTanagw. och пpoцecтi :Y3ere acwpy npo^crnge SARS-CoV-2 BHpycw Ko:aMbiH :acymaHbi napa3HTTiK :onMeH naMganaHagw (cypeT 2).
CypeT 2 - SARS-CoV-2 BHpycbiHbiR :acymaFa eHy :onbiHbiR cxeMacw [27]
YmiHmi caTwcw, BHpycTbiR PH^ peпnнкaцнacн :ypegi. On, eKiHmi Ke3eKTeri PH^ peпnнкaцнflCbIнa :ayanTH aKybßgapgbiR TY3inrernHeH KeMiH BHpycTbi; PH^-ga peпnнкaцнa пpoцeci :^mhc icTeMgi. ATanFaH, SARS-CoV-2 - no3HTHBTi PH^-nbi BHpycTap KaTapwHa :aTagw. Peпnнкaцнa Ke3eRi a^KTanFaHHaH cor, no3HTHBTi PH^-gaH HeraTHBTi PH^ TY3inegi.
Осыдан кейiн, тертiншi сатысы вирустыц курылым белшектерiнiц тYзiлуi басталады. SARS-CoV-2-нiц негативтi РН^-дан жаца вирустардыц курылым белшектерi тYзiле бастайды. Негативтi РН^-ны материал кезi ретшде пайдаланып, бiрнеше мРН^-лар тYзiледi. Нэтижесшде, мРН^-дан вирустыц гликопротеин S акуызы, мембрана акуызы (М), кiшкентай акуыз (Е), нуклеокапсид (К) секiлдi курылымдык акуыздар тYзiледi. Бесiншi сатысында, курылымдык акуыздар ЭПТ-дыц iшiнде курылганнан кешн, акуыздар мен РНК Гольджи аппаратына етедi. Гольджи аппаратыныц iшiнде курылымдык акуыздар мен позитивт РНК толык вирус ретiнде бiрiгiп, визикула «кетршштердщ» iшiне орналасады. Алтыншы сатысында, визикуланыц iшiндегi толыгымен жинакталган вирус экзоцитоз процес аркылы жасушадан сыртка шыга бастайды. Толык дамып жетiлген вирус, баска жасушаларга шабуыл жасайды [19-28].
Агзаныц вируска тезiмдiлiгi дурыс тамактану жYЙесiмен тыгыз байланысты. Табиги биологиялык белсендi заттармен байытылган тагам енiмдерi агзага вирустык инфекциялардыц каупiн азайтуы мYмкiн [29]. Иммунитеттi жаксартуда тагам курамындагы мундай компоненттер В жэне Т жасушаларын белсендiлiгiн арттырады жэне олардыц кебеюiне, туа бiткен жэне адаптивт иммундык жауаптыц индукциясы мен модуляциясына катысады [30-31]. Келтiрiлген мэлiметтер негiзiнде, оцтайлы тамактану иммунитеттiц COVID-19-Fа карсы турудыц бiрден-бiр туракты эдiсi.
Тагам енiмдерiнiц iшiнде CYт жэне CYт енiмдерi курамындаFы баFалы акуыздарымен иммундык жYЙеге пайдалы [32]. Эпидемиологиялык зерттеулер сиыр, бие жэне тYЙе CYтiн туракты тутыну адамдарда бактериялык жэне вирустык инфекциялардыц темен таралуымен сипатталган [33-34]. СYттегi мацызды компоненттерiнiц бiрi - лактоферрин (ЛФ), ол трансферриндер тукымдасына юретш кеп функциялы акуыз.
Лактоферрин акуызыныц иммунопротекторлык жэне кабынуга карсы касиеттерi SARS-CoV-2 тэрiздi респираторлык вирустардан коргауды камтамасыз ететiндiгi бiркатар гылыми макалаларда керсетiлген [9;15;35]. ЛФ-нiц COVID-19-ге карсы иммундык коргаудагы потенциалын зерттеу Yшiн оныц биологиясын, курылымын, онымен байланысатын мембраналык рецепторларын, иммуномодулярлык жэне вируска карсы механизмдерш, сонымен катар кездерiн бiлу кажет. ¥сынылган макалада лактоферриннiц вирустарга карсы профилактикалык, терапиялык, иммунопротекторлык жэне механизмш карастырып, лактоферрин акуызыныц COVID-19 емдеудщ косымша эдiсi ретiндегi релi талкыланган.
Лактоферриннщ цурылымы жэне физика-химиялыц цасиет1 ЛФ акуызы -трансферриндер (ТФ) тобына жататын гемсiз темiр байланыстыргыш гликопротеин. Лактоферрин алгаш рет 1939 жылы сиыр CYтiнен (сурет 3), ал 1960 жылы ана CYтiнен белшш алынды. ЛФ-тiц аминкышкылдык тiзбегi жануарлардыц 10 тYрiнен (адам, сиыр, тышкан, жылкы, доцыз, ешкi, кой, буйвол жэне тYЙе) аныкталган [36-37]. ЛФ акуызы молекуласыныц узындыгы шамамен ~700 аминкышкылы калдыгынан тYзiлген бiр полипептидтш тiзбектен турады. Молекулалык салмагы ~ 76-80 кДа. Адам мен тышкан ЛФ акуызы бойынша бiрiншi ретпк курылымыныц уксастыгы 70%, адам мен сиырда - 69%, сиыр мен тышканда - 63% [38]. Адам ЛФ акуызы бiрiншi реттiк курылымы адам сарысу ТФ жогары децгейде уксастыкка ие (~ 59 %). Альтернатив^ промоторлар - Р1 жэне Р2 -эсершен ЛФ геншщ транскрипциясы екi енiмнiц тYзiлуiне экеледг мРНК ЛФ жэне дельта-ЛФ (А - ЛФ) [39]. Д-ЛФ-де №соцгы сигналдык тiзбегi болмау себебшен оныц ешкандай кызметi жок [40]. Адам ЛФ изоэлектрлш нYктесi эдебиет кездершде 8.0-8.5 [41]; 8.7 жэне 9.7 аралыгында ауыткиды [42].
ЛФ акуызыныц полипептидтш тiзбегi глобулярлы ею гомологты С жэне N белштерден куралган (сурет 3). Екi белштеп амин кышкылдык курамыныц уксастыгы 37% - га жуык. N белш, полипептидтiк тiзбектiц К-соцын (1-332 амин кышкыл калдыктары), С белiгi С-соцын (345-691 амин кышкыл) курайды. Олар кыска альфа-спиральмен (333-344 амин кышкылы) байланыскан, осы байланыс молекулага косымша сертмдшк касиет бередi [37]. Эр бiр белiк эллипсоид пiшiндi, келемдершщ реттiлiгi 55*35*35 А. Акуыз
молекуласы симметриялы емес, ce6e6i бeлiктер 6ip-6ipiHe ~150° бурышта бурылыс жасаган жэне 25Ä ыгыскан. 3p6ip 6eлiк ез кезегiнде екiншi реттiк курылымы ете уксас екi доменнен турады [37; 43]. Молекула ~ 43% а - спиральдан жэне ~ 27% ß - катпардан турады. Акуыз курылымында 16 дисульфидтiк 6айланыс 6ар, оныц 6 жу6ы екi белште тец, ал калган 4 жу6ы С-6eлiгiнде орналаскан. Iрi кара лактоферрин акуыз молекуласыньщ жалпы схемесы Yшiншi суретте келтiрiлген.
Сурет 3 - 1р1 кара лактоферрин акуызы молекуласыныц схемасы N1 жэне N2 домендер1 сэйкесшше сары жэне кызгылт, ал C1 жэне C2 домендер1 сэйкесшше жасыл жэне кек тYCтермен, ал белштер (ло6) арасындагы езара 6айланысты спираль кызгылт сары тYCтi, ею тем1р атомы кызыл шар тYрiнде керсетшген [44]
ЛФ екi тYрлi формада кездеседi: апо (темiрмен каныкпаган акуыз) жэне холо (6елсендi орталыгында Fe3+ 6ар) 6олады. ЛФ акуыз молекуласы Fe3+ екi ионымен керi 6айланысуга ка6iлеттi. Эр6iр 6eлiктегi домендер (N1, N2 жэне C1, C2) аралыгындагы терещрек аймакта темiр - 6айланыстырушы сайттар 6ар, олардыц кeлемi ~ 42 Ä курайды. Темiрдiц эр6iр атомы терт акуыздык лигандпен Yйлестiрiлген: Tyr-92 жэне Tyr-192 фенолят-иондардагы (сэйкесiнше Tyr - 435 жэне Tyr - 528 С-соцында) ею оттегi атомдарымен, His - 253 (His -597) имидазолдагы Ns2 азот атомымен жэне Asp-60 (Asp-395) кар6оксильдегi оттегiмен. Темiрдiц эр6iр атомыныц октаэдрлiк ортасы 6ар, дегенмен де, терт акуыз лигандты алты позицияныц тек тeртеуiн гана алып жатады. Зерттеулерге сэйкес калган екi позицияда СОз2-немесе НСОз- аниондары орналасады [37; 43].
ЛФ-тщ темiрмен 6айланысу схемасы кeрсетiлген (сурет 4). Темiр атомы кызыл шар тYрiнде 6ейнеленген, ал ЛФ-тщ езара эрекеттесетiн аминкышкылдарыныц калдыктары сары тYCтi. ^алдык сандар N-соцына сэйкес келедi, ал С-соцыныц тиiстi аминкышкылы калдыктары жакшада орналаскан [44].
Анион пептидтщ оц зарядталган N-соцымен жэне Arg-121 радикалымен 6айланысады. Мутагенез 6ойынша жасалган тэжрибиелерде, белсендi орталыктагы кез келген 4 калдыгыныц алмастырылуы темiрдi байланыстыру кабшетшщ бiрден нашарлауына алып келетiндiгi дэлелденген. Arg-121 калдык бойынша мутация да дэл осындай эсерге алып келедi [38; 43].
ЛФ акуызына темiр берш эрi кайтымсыз (Kd~10-20 M-1) байланысады. ЛФ акуызы темiрдi тiптi бэсекелес лиганд (мысалы, цитрат) жэне рН мэш 3,0 болган жагдайда да байланыстыруга ка6iлеттi, ал ТФ тобыныц баска акуыздары рН~5.5 болганда темiрдi босатады [37]. ЛФ мен ТФ эртYрлi касиеттерi ЛФ-гы екi белштщ (лобтыц) Yйлесiмдi байланысымен аныкталады [38]. ЛФ С-белшне темiрдiц байланысуы ^белштеп оныц
(тeмipдщ aкyызFa) бaйлaныcын aнaF¥pлым т¥paктaндыpaды. M¥ндa N-бeлiкпeн ^^maca^rn C-coцындaFы aльфa-cпиpaль мaцызды кызмeт aткapaды. ТФ-дe ocы к^былыстьщ бoлмayы ЛФ-гi eкi бeлiктi бaйлaныcтыpaтын пeптид к¥PылымындaFы epeкшeлiкпeн тYciндipiлeдi. Бapлык cипaттaлFaн ЛФ ocы пeптид aльфa-cпиpaль тYзeдi, aл ТФ-дa o^ih элаз, тYзy, peтciз к¥pылымы бoлaды. Aльфa-cпиpaльдщ мыктылыFы eкi бeлiктщ тыFыз бaйлaныcyын кaмтaмacыз eтiп, N-бeлiккe тeмipдщ бaйлaныcyын т¥paктaндыpaды. Hэтижeciндe, тeмipдщ бocaп шы^ыта (ЛФ-дaн) эcep eтiп pH мэнш тeмeнгi шeккe кapaй ыFыcтыpaды. ТФ мoлeкyлacындa лизиннщ - Lys-206 жэ^ Lys-296 -кaлдыктapыньщ бoлyы ЛФ жэ^ ТФ кызмeттepiндeгi aйыpмaшылыFынa ceбeпшi бoлyы мYмкiн. Оcы eкi ^лды; epeкшe cyтeктiк бaйлaныc тYзeдi. Aдaм ЛФ aкyызы Arg-210 жэнe Lys-301 ocы жуп кaлдыктapмeн aлмacкaн. Дeгeнмeн, cиыp, бyйвoль, жылкы жэнe тYЙe ЛФ aкyызындa ТФ-Fы пoзицияFa y;cac лизиннщ eкi кaлдыFы бoлaды - Lys-2010 жэнe Lys-301. Aлaйдa, o^i eкi кaлдык apacындa бaйлaныc тYзiлмeйдi, cэйкeciншe aкyыздapдaн epeкшeлiк бaйкaлмaйды [37-38].
Cypeт 4 - Лaктoфeppиннiц тeмipдi бaйлaныcтыpy cхeмacы [26]
Тeмipдщ aкyызбeн бaйлaныcyы жэнe бocaп шыFyы ЛФ aкyызындa к¥Pылымдык eзгepicтepгe aлып кeлeдi [37]. ЛФ aкyызы aшык к¥pылым жaFдaйындa тeмipмeн бaйлaныcaды: eH aлдымeн aниoнмeн бaйлaныcып, нэтижeciндe лигaндтapдьщ ыFыcyынa aлып кeлeдi. Cocын, тeмip ЛФ aкyызы мoлeкyлacымeн тoлык бaйлaныcып, apы кapaй ЛФ eтe ыкшaм к¥Pылымдык пiшiнгe, яFни жaбык к¥pылымдык тшшге ayыcaды. ЛФ aкyызыныц aпo-фopмacы мeтaллдapдьщ бacкa дa иoндapымeн бaйлaныca aлaды, эдeттe жoFapы oh зapядты иoндap (Cr3+, Co3+, Mn3+, Al3+, Ga3+, Cu2+, Zn2+, Cd2+, Ni2+, лaнтaнoидты иoндapы) [37-38]. AтaлFaн мeтaлл иoндapы ЛФ aкyызынa Fe3+ бaйлaныcaтын aмин кышкылдap apкылы бaйлaныcaды. Coнымeн кaтap, ЛФ aкyызыньщ пeптидтi тiзбeктщ yчacкeлepi кeмeгiмeн 70 дeйiн Fe3+ иoндapын бaйлaныcтыpa aлaтындыFы зepттeyлepдe кepceтiлгeн [45]. Hэтижeciндe, ЛФ aкyызы 15-16 мoлeкyлaлapынaн т¥paтын зaт тYзiлeдi. Оcы зaт нaтивтi aкyызFa кapaFaндa т¥paктылыFы eтe жoFapы. Т¥paктылыктьщ жoFapлayы ocы зaттaFы эpтYpлi ЛФ aкyызы мoлeкyлaлapыньщ к¥Paмындa бoлaтын Fe3+ жэнe HCO-3 иoндapыньщ apacындaFы элeктpocтaтикaлык бaйлaныcкa нeгiздeлгeн [37].
ЛФ aкyызы глoбyляpлы гликoпpoтeин [39]. Кeмipcy фpaгмeнтi aкyызбeн acпapaгиннщ (Asn-137 жэнe Asn-490) aмидтi aзoты ap^L^i гликoзидтiк бaйлaныc тYзeдi. ЛФ к¥PaмындaFы гликoзидтiк бaйлaныcтapдыц caны жэнe opнaлacyы жaнyapлapдыц тYpлepiнe бaйлaныcты ayыткиды [37; 39]. ЛФ-нщ кeптeгeн фyнкциялapы o^ih эpкeлкi тapaлFaн бeттiк зapядымeн aныктaлaды. Он зapядтaлFaн Yш ayмaкты бeлiп кepceтyгe бoлaды: N-
соцында (1-5 калдыктар), бiрiншi альфа-спиральде (12-31 калдыктары) жэне ею 6eлiк аралыгында. Адам ЛФ-нщ N-соцындагы GRRRR сигналдык тiз6егi осы акуыздыц ядрога енуiн камтамасыз етедь Осылайша, ол транскрипциялык фактор ретшде кызмет аткарады. Жогарыда келтiрiлген сигналдык тсзбек тек адам ЛФ тэн, баска жануарларда болмайды [37].
Лактоферринтц кездесетт квздерь ЛФ акуызы эртYрлi CYткоректiлердiц шырышты эпителий жасушаларынан бeлiнедi [46-50]. ЛФ акуызы барлык экзокриндi бездер сeлдерiнен: кез жасында (2 мг/мл [41; 46-50] немесе 0,4 мг/мл), сшекей (0,013 мг/мл), назальдi жэне бронх, ет селдершен (0,0042 мг/мл), панкреатит селшен, урык суйыктыгынан (0,518 мг/мл), зэр (0,00005 мг/мл), тер (0,0025 мг/мл) аныкталган. ЛФ ете кеп мелшерде CYтте (1,28 мг/мл) жэне уызда (7 мг/мл немесе 3,2 мг/мл) кездеседi [37; 51]. Суттеп казеиннен кейiнгi ец кец таралган акуыз. Сиыр CYтiнде ЛФ концентрациясы лактация кезещне, сиыр тукымына байланысты 31,78 - 485,63 p,g.mL-1-re аралыгында eзгередi [51], ал оныц уыздагы концентрациясы 1-5 mg/mL. Сонымен катар, тYЙе CYтiндегi лактоферрин концентрациясы 20-2100 pg.mL-1 [52-53] курайды [30]. Зерттеулер керсеткендей, тYЙе cy^^ лактоферринi калыпты CYтте 0,02-ден 7,28 (jg.mL^-re дейiн eзгередi, 6iрак лактоферриннщ максималды мeлшерi телдегеннен кейiн шамамен 48 сагатта 2,3 g.L-1 мeлшердi курайды [54]. Iрi кара мал мен адам ЛФ-нщ биологиялык белсендшп уксас болгандыктан, лактоферрин акуызыныц колжетiмдi кeзi ретiнде жануарлар CYтiн пайдалануга мYмкiндiк 6ередi. СYт 6ездерiнде ЛФ акуызыныц белшуш (транскрипция жэне трансляция) пролактин бакылайды, ал жыныс жолдарында ЛФ акуызы экспрессиясын стероидты гормон - эстроген индицурлейдь ^ан тYзiлу жYЙесiнде ЛФ миелоциттердiц пiсiп-жетiлу сатысында дамып жаткан нейтрофилдерде экспрессияланады (синтезделед^ [37]. Нейтрофилдердiц екiншiлiк тYЙiршiктерiнде корга жинакталады. Олардагы акуыздыц мeлшерi нейтрофилдердщ 15 мкг/106 курайды [40]. Сонымен катар, ЛФ каннан (0,001 мг/мл) жэне амнион суйыктыгынан (0,006 мг/мл) аныкталган. ^андагы калыпты мeлшерi шамамен 1 мкг/мл, дегенмен кабыну кезшде оныц мeлшерi 200 мкг/мл дешн жетуi мYмкiн [37].
Лактоферриннiц Yш тYрлi изоформасы 6елгiлi, оларга альфа ЛФ (LF-а), бета ЛФ (LF-ß) жэне гамма ЛФ (LF-g) жатады. LF-a темiрдi байланыстырады, бiрак калган екi изоформалар LF-ß жэне LF-g темiрмен байланыспайды [55-57].
Лактоферринтц иммуномодуляциялъщ эсер1 ЛФ акуызыныц мембраналык рецепторлармен байланысу механизмi, оныц биологиялык белсендшгш кeрсетедi. ЛФ келесi рецепторлармен байланысады: TLR2, TLR4 [58], CD14 [59], цитокиндi рецепторлар [60] жэне Intelectin-1 [61]. Бул рецепторлардыц барлыгы жасушалар мен тiндердiц кептеген тYрлерiнде, соныц iшiнде лимфоциттерде жэне шек эпителий жасушаларында кездесетiндiгi туралы айтылган [62]. ЛФ акуызыныц рецепторлармен байланысу кабшет оныц вируска карсы иммунитета жогарылату мен агзаныц корганыс механизмi Yшiн мацызды. ЛФ акуызы езшщ иммуномодуляциялык 6елсендiлiгiн инфекциялык молекулалармен бэсекеге тYсу аркылы жYзеге асырады, осылайша белшектердщ косылуын тежейдi [63]. ЛФ акуызыныц ерекшелш, гепаран сульфаты протеогликандарымен (HSPGs) байланысады, оны SARS-CoV жэне адамныц коронавирустык NL63 жасушага беюту жэне енпзу рецепторы [6; 64]. SARS-CoV-2 eзiнiц функционалды рецепторы ретшде ACE2^i колданады, 6iрак гепаран-сульфатты протеогликандармен (HSPG) байланысуы мYмкiн, eйткенi SARS-CoV ею рецепторды да байланыстыратындыгы аныкталган, алайда SARS-CoV-2 Yшiн HSPG^i колдану туралы зерттеулер толык дэлелденбеген. Эпителий жасушалары зиянды заттардыц енуше кедергi келтiретiн алгашкы физикалык тоскауыл болып саналады жэне туа пайда болган иммунитетте мацызды рел аткарады [65].
ЛФ акуызы иммундык жYЙеде жэне инфекция мен кабынудыц корганыс жYЙесiнде мацызды рел аткарады [61]. Оныц кейбiр иммуномодуляциялык эсерлерi липополисахаридт (LPS) кешендерге негiзделген. ЛФ акуызы вируспен байланыскан LPS-пен байланысады, осылайша вирустыц жасушага енуiне жол бермейд^ 6iрак вирус жасушага енген болса, ол гранулоциттер мен макрофагтар сиякты киллер жасушаларды
biHTanaHgbipy apKbinbi BupycrbiR Ke6eroiH Te:eMgi [65]. HO aKybi3bi цнтoкннgep/хнмoкннgep MeH nepoKcugTep eHgipiciH peTTeyre [66-67], HMMyHgbiK :acymanapgbi, aTan aMTKaHga MaKpo^arrapgbi, HeMTpo^ungepgi, 6a3o$ungepgi, эoзннo$нngepgi, Maci^HTTepgi :aHe geHgpuTTiK :acymanapgbi 6enceHgipyre :aHe nponн$epaцнflnayFa KaTbicagbi [35]. ^acymanapgbiR $aroцнтriк Ka6ineTi HO aKybi3biHbiR 6enrini 6ip 6aMnaHbicTbipymbi caMTrapgbi TaHy apKbinbi Mogyn^uanaHagbi [68].
^gpoFa :eTKi3inreH HO a^yw3w fl,H^-MeH 6aMnaHbicagbi :aHe ap TYpni curHan 6epy :ongapbiH 6enceHgipegi [41; 69]. HO-HiR iciK HeKpo3w anb^a - ^aKTopw :aHe HHTepneMKHH (IL) -1, IL-2 :aHe IL-6 ch^ktw Ka6brnyFa Kapcw цнтoкннgepgi Te:ey 6enceHginiriH HHTep^epoHraMMa apKbinbi aHbiKTanFaH. CoHbiMeH KaTap, :acymanbiK geRreMge HO KaHHbiR nonuMop^Tbi agponwK :acymanapwH Ka6bingaygbi KYmeMTegi :aHe мнenonoэтнкanbIк пpоцecтi biHTanaHgbipagbi [41]. CoHgaM-aK, co3binManbi aypynapga HO nepu^epuanbiK KaHgaFH Th1 цнтoкнн npo^unrn :oFapwnaTagw [70].
HO-HiR geгpagaцнflCbI H3TH:ecrnge anbiHFaH naктo$eppнцнн nenTugi, Ka6biHy npo^cimR 6acTanywH meKTeMgi, IL-10 eHgipiciH KYmeMTegi, ocwnaMma Th2 (Ka6brnyFa Kapcw) Tapi3gi 6enceHginiriH biHTanaHgbipagbi. HO ннтep^epeнцнacw $u6po6nacr remmR экcnpeccнacw apKbinbi naMga 6onagbi, aKyw3 eHgipiciH Mogyn^HanaMgbi :aHe :acymagaH Tbic MaTpu^Hbi e3repTegi, ocwnaMma HMMyHgbiK :acymanapgbiR Ko3FanFbimTbiFbiH aprrbipagbi [71].
HaKTo^eppHH aKybi3biHbiR BupycKa Kapcbi acepi. HO aKybi3bi BupycKa Kapcbi KacueT agaM MeH :aHyapnapgbi HH^e^uanaMTbiH PH^ :aHe ^H^-BHpycTapgMR KenminiriHe Kegepri KenTipegi. HO aKybi3bi BupycrapFa Kapcbi acepimR eKi TYpi 6enrini. EipiHmigeH, Ko:aMbiH :acymaMeH BHpycTHR 6aMnaHbicy caTbicbiH Te:eyi mymmh, Mbicanbi repnec, B renaTHTi, agaMHHR цнтoмeranoвнpycw, ageHo-, poTa- :aHe nonuoBHpycrap. EKiHmigeH, 3aKbiMganFaH :acymanapga BHpycTHR pennнкaцнa npoцeciн Te:eMgi (C :aHe G renaTHTi, ®HTC). 3aKMMgany npoцeciнiR anFamKbi caTbicbrnga aKybi3 BupycKa Kapcbi acep KepceTe anagbi [37].
HO aKybi3bi BupycTMK HH^e^uAHbi HHru6upneyi Ko:aMbiH :acymaMeH BupycrbiR 6aMnaHbicybiHa Kegepri KenTipy acepiMeH TYciHgipinegi, 6on:aM 6oMbrnma, OFaH :acymaHbiR 6eTKi :aFbiHga opHanacKaH MoneKynanap KaTbicybi MYMKiH. rnroK03aMHHrnuK0Hgap, Heri3iHeH renapaH cynb^arrap, cYTKopeKTinep :acymanapbiHbiR 6eTKi :aFbiHga 6onaTbiH eTe KYmTi aHHOHgap, ce6e6i onapFa :oFapbi gape:ege cynb^arraHy tsh. 0Te Ken Menmepge Tepic 3apagTbiR 6onybi H3TH:ecmge rnroK03aMHHrnuK0Hgap KaTHOHgapMeH, aKybi3gapMeH, ^epMeHTTepMeH, цнтoкннgepмeн, xeMOKHHgepMeH, nunonpoTeuHgepMeH, coHMMeH KaTap apTYpni naToreHgepMeH :aHe BupycTapMeH 6aMnaHbicybiH KaMTaMacM3 eTegi. KeRiHeH TapanFaH api 3epTTenreH MexaHH3Mre caMKec, HO aKybi3bi renapaH cynb^aTneH 6aMnaннcнn, BupycTMR :acymaMeH anFamKM KaTMHacyMHa Kegepri KenTipegi :aHe ohhr зaкнмgaнyннaн KopFaMgb
[41].
KenTereH 3epTTeynep, cohhr imiHge in vitro :Ypri3inreH 3epTTey H3Tu:eci KepceTKeHgeM, agaM KaHMHgaFM :aHe cYTiHgeri 6apnbK aKybßgapgbiR imiHge TeK HO aкyнзн FaHa ®HTC -Ke Kapcb acepi eTe :oFapb. Eyn к¥6нnнc Ko:aMbiH :acyma imiHge Bupyc pennнкaцнacнн HHru6upney KacueTTepiHe Heri3genreH [37]. EacKa 3epTTeynep H3Tu:eciHe caMKec, HO aкyнзнннR ano-$opMacbi poTaBupycTMR 6eniKTepiMeH 6aMnaннcнn, reмaarrnroтннaцнaFa :aHe :acyma peцenтopnapнмeн BupycTMR KaTMHacKa TYcyiHe Kegepri :acaMgM [68]. HO aKybi3biHbiR och aHTHBupycTMK 6enceHginiri aкyнзgнR Fe3+, Fe2+ HOHgapMeH, coHMMeH KaTap Mg2+ :aHe Zn2+ ch^kth eKi BaneHTri MeTann uoHgapwMeH KaHHFyw apTKaH caMbiH TeMeHgeMgi. Corfh 3epTTeynep H3Tu:eciHe caMKec (2009), ageHoBupycTHR нeMтpanнзaцнacннa HO BHpycTHR K¥pbinbiMgbiK III :aHe lila aKyw3gapwMeH TiKeneM 6aMnaHHcyw HKnan eTegi [69]. HO aKybi3bi coHHMeH KaTap :acymagaFbi HaKTH 6ip BupycTapgwR ннтepнanнзaцнacнн 6¥FaTraMgbi. E^FaH nonuBupyc Tun I, KapanaMwM repnec Tun I :aHe II6 цнтoмeranoвнpyc :aTagw [36].
HO aKybi3bi Ko:aMwH :acymaHHR KopFaHwc MoneKynacw peTiHge eTe MaRH3gw :aHe ohhr $H3HonoruflnbiK 6enceHginiri Ka6wHyFa, 6aKTepu^Fa, BupycKa Kapcw, aHTuoKcugaHTTH,
иммуномодуляциялык, анти-карциногенд^ антипротозоанды жэне сацыраукулактарга карсы [36]. Зерттеулерге сэйкес ЛФ акуызыныц темiрдi устап калу ка6iлетi иммундык жасушалардыц козгалгыштыгын модуляциялауда жэне патогендi микроорганизмдердiц eсуiн тежеуде де тиiмдi [51].
Коронавирус жэне лактоферрин. SARS-CoV инфекциясы кезiнде кожайын жасушаныц (агзаныц) вируска карсы иммундык реакциясы басталады. Туа пайда болган иммундык жауап вирустык инфекцияны тежеуде мацызды рел аткарады. SARS-CoV вирусына карсы туа пайда болган иммундык жауапты белсендендiруге ЛФ акуызыныц эсерi болатындыгы айтылган [11]. ЛФ акуызы SARS-CoV инфекциясы кезшде NK жасушаларыныц 6елсендiлiгiн арттырып, нейтрофилдердiц агрегациясы мен адгезиясын ынталандыратынын керсеткен. Алайда ЛФ акуызыныц биологиялык 6елсендiлiгi толык зерттелмеген.
А
SARS COV
tt Гу Ч^Т т
HSPG АСЁЗ HSPG ДСЕ2
Сурет 5 - SARS-CoV жасушага енушщ модел1 жэне SARS-CoV инфекциясындагы лактоферринищ
корганыш рел1 [15]
(A) Жасушага SARS-CoV ену процесшде HSPG-лер мацызды рел аткарады. HSPG-мен байланысу алацдары SARS-CoV мен кожайын жасуша арасындагы алгашкы байланысуына мYмкiндiк 6ередi. SARS-CoV вирусы HSPG жэне АСЕ2-мен байланысуы аркылы жасуша мембранасына 6екiтiлiп, агзага накты юру рецепторларын (АСЕ2) iздейдi, осылайша жасушага енедь (B) ЛФ акуызы HSPG-мен байланысуы аркылы SARS-CoV инфекциясын блоктайды. ЛФ акуызы жасуша 6етiндегi HSPG-ге орналасады жэне вирус пен кожайын жасушалары арасындагы алдын-ала езара эрекеттесуге жэне кейiнгi iшкi процестерге жол бермейдi [15].
Вирустар эдетте жасуша мембранасында ортак молекулаларды жасушаларга енуш жецiлдету Yшiн пайдаланады. Бул молекулалар, соныц iшiнде гепаран сульфатыныц протеогликандары (HSPGs) жасуша 6етiндегi алгашкы вируспен байланысу аймактарын камтамасыз етiп кожайын жасушага енуге алгашкы байланыс орнатуга кeмектеседi [38]. ЛФ акуызы кептеген жасушаларда болатын HSPGs-пен байланыстыру аркылы кейбiр вирустарды агзаныц iшкi жасушаларына енуiне кедергi келтiретiндiгi кeрсетiлген [39].
ЛФ акуызыныц бул касиет кожайын жасушаны немесе агзаны вирустык инфекциялардан коргайды. Осы тужырымдарга CYЙене отырып, ЛФ акуызыныц SARS-CoV-ге карсы тагы 6iр эсерi оныц кожайын жасушаларында кец таралган HSPGs-молекуласымен байланысуымен болжанады. Жогарыда келтiрiлген мэлiметтерде, SARS псевдовирусыныц жасушага ену процесшде жасуша бетшдеп АСЕ2 мен HSPGs рецепторлары мацызды рел аткаратындыгын керсетелген (сурет 5). ЛФ акуызы SARS псевдовирус инфекциясын АСЕ2 мен HSPGs-пен байланысу аркылы бугаттай алады, бул SARS-CoV шабуылынан кожайын жасушаныц иммундык жYЙесiнде корганыс рeлiн аткара алады деп болжайды.
COVID-19 пандемиясымен ^ресу эдiстерi шектеу мен гигиеналык шараларды сактаумен катар, вируска карсы препараттар мен вакциналар табылганымен, элi де жан-
«aKTH 3epireygi Ka«eT eTegi. HO aKyH3H TaFaMgHK Kocna peTiHge BHpycTapFa, cohhih imiHge, SARS CoV-ra Koca anFaHga, Ke« ayKHMgbi BHpycTapFa KapcH naMganaHy MYMKiHminiri 3epTTenreH. ATanFaH 3epTTey «yMbicTapH öip TybicKa «aTaTHH SARS CoV-2-re «aKHH GonyHMeH kh3hkth [9; 15]. SARS-CoV «aHe SARS-CoV-2 räGeKTepimH yKcacTHFH 79% K¥PaMgH «aHe onapgH« pe^nTopnapMeH GaMnaHbicaTbiH goMeH kyphmhmhi ga 6Te yKcac. CoHHMeH KaTap, HO aKyH3H TbimKaH-KopoHaBHpycHHgaFH «acyma GeTiHgeri renapaH cynb^aTH npoTeornuKaHgapHMeH (HSPGs), agaMHH« KopoHaBupycH hCOV-NL63 [64] «aHe SARS-CoV [15] GaMnaHbicybi BupycTH« GenceHginiriH Te«eMgi. EipaK, SARS-CoV-2 Ko«aMbiH «acymanapHHa eHyiHe HO aKybi3biHbi« acepi TypanH ganengeHreH 3epTTeynep «ok [65]. KeMGip Hay^acTapga COVID-19 eniMi TeK BHpycTHK HH^e^HAFa GaMnaHbicTbi eMec, runep KaGHHy «aHe цнтoкннgiк aypy cuHgpoMHMeH ge GaMnaHbicTbi, Gyn «egen pecnupaTopnHK KYM3enicKe «aHe ogaH KeMiH eniMre aKenegi [72]. COVID-19 aybip «aFgaMnapHHga цнтoкннgep MeH HHTepneHKHH IL-6, iciK HeKpo3H ^aKTopH (TNFa) «aHe ^eppHTHH geHreMimH «OFapHnayH GaMKanagH [65]. HO aKyH3H BHpycTHK HH^e^HAFa KapcH HMMyHgHK «aHe KaGHHy pea^HacbiH Mogyn^H^nayH MYMKiH, coHgHKTaH HO aKyH3H COVID-19 aybip «aFgaMnapHH KocHMma eMgeyre Heri3 Gona anagH.
^opuTHHgu
CYTTi« HO aKyH3H Ma«H3gH TaFaMgHK Kocna peTiHge BHpycTHK maGyHngapFa KapcH TuiMgi, KenTereH BHpycTHK GenmeKTepMeH HeMece BHpycTHK pe^nTopnapMeH GaMnaHbicbin, HMMyHgHK «yMem «aKcapTyFa KeMeKTecegi. CoHHMeH KaTap, HMMyHoMogyn^H^nHK, KaGHHyFa «aHe BHpycKa KapcH epeKme KacHeirepi Gap naKTo^eppHH aKyH3H COVID-19 YmiH npo^unaKTHKanHK, angHH-any «aHe KocHMma eMgey agici peTiHge KYHgH noтeнцнanFa He GonyH MYMKiH, ceGeGi on BHpycTHK HH^e^HAHbi ga, Ko«aMbiH «acymaHHHHH HMMyHgHK pea^HAcbiH ga KaMTHgH. AnaMga, SAR-CoV-2 BHpycH GoMbrnma naKTo^eppHH aKyH3HHH« TaFaMgHK KocnacH TypanH KocHMma 3epTTeynep MeH a3ipneMenepgi Ka«eT eTegi.
3fle6neTTep:
1 Wang L.F., Shi Z., Zhang S., Field H., Daszak P., Eaton B. Review of bats and SARS. Emerg InfectDis, 2006, 12(12): 1834-1840.
2 Ge X.Y., Li J.L., Yang X.L., et al. Isolation and characterization of a bat SARS-like Coronavirus that uses the ACE2 receptor. Nature, 2013, 503(7477):535-538.
3 Chen Y, Guo D. Molecular mechanisms of Coronavirus RNA capping and methylation. Virol Sin., 2016, 31(1):3-11.
4 Cui J., Li F., Shi ZL. Origin and evolution of pathogenic coronaviruses. Nat Rev Microbial, 2019, 17(3): 181-192.
5 Cauchemez S., Van Kerkhove M.D., Riley S., Donnelly C.A., Fraser C., Ferguson N.M. Transmission scenarios for Middle East respiratory syndrome Coronavirus (MERS-CoV) and how to tell them apart. Euro Surveill, 2013, 18(24):20503.
6 Guan Y., Zheng BJ., He YQ., Liu XL., Zhuang ZX., et al. Isolation and characterization of viruses related to the SARS coronavirus from animals in southern China. Science, 2003, 302:276-278.
7 Rahman A., Sarkar A. Risk factors for fatal middle east respiratory syndrome coronavirus infections in Saudi Arabia: analysis of the WHO Line List, 2013-2018. Am J Public Health, 2019, 109(9): 1288-1293.
8 Memish Z.A., Zumla A.I., Al-Hakeem R.F., Al-Rabeeah A.A., Stephens G.M. Family cluster of Middle East respiratory syndrome coronavirus infections. N Engl. J Med, 2013, 368(26):2487-2494.
9 Chen Y., Liu Q., Guo D. Emerging coronaviruses: genome structure, replication, and pathogenesis. Journal of Medical Virology, 2020, 92:418-423.
10 Zhu N., Zhang D., Wang W., Li X., Yang B., Song J., Niu P. A novel coronavirus from patients with pneumonia in China, 2019. New England Journal of Medicine, 2020, 382:727-733.
11 Shereen M.A., Khan S., Kazmi A., Bashir N., Siddique R. COVID-19 infection: Origin, transmission, and characteristics of human coronaviruses. Journal of Advanced Research, 2020, 94:91-98.
12 Kuchler H., Cookson C., Neville S. The $2 bn race to find a vaccine. Financial Times, 2020, 7.
13 Du L., He Y., Zhou Y., Liu S., Zheng B., Jiang S. The Spike protein of SARS-CoV-a target for vaccine and therapeutic development. Nature review Microbiology, 2009, 7:226-236.
14 Chen J., Subbarao K. The Immunobiology of SARS. Annu Rev Immunol, 2007, 25:443-472.
15 Lang J., Yang N., Deng J., Liu K., Yang P., Zhang G., Jiang C. Inhibition of SARS pseudovirus cell entry by lactoferrin binding to heparan sulfate proteoglycans. PLoS one, 2011, 6: e23710.
16 Zhu N., Zhang D., Wang W., Li X., Yang B., Song J., Niu P. A novel coronavirus from patients with pneumonia in China, 2019. New England Journal of Medicine, 2020, 382:727-733.
17 Bartlam M., Yang H., Rao Z. Structural insights into SARS coronavirus proteins. Current Opinion in Structural Biology, 2005, 15:664-672.
18 Li F., Li W., Farzan M., Harrison S.C. Structure of SARS Coronavirus Spike Receptor-Binding Domain Complexed with Receptor. Science, 2005, 309:1864-1868.
19 Wu F., Zhao S., Yu B., Chen Y-M., Wang W., Song Z-G., et al. A new coronavirus associated with human respiratory disease in China. Nature, 2020, 579(7798):265-269. doi: 10.1038/s41586-020-2008-3.
20 Zhou P., Yang X., Wang X., Hu B., Zhang L., Zhang W., et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature, 2020, 579(7798):270-273. doi: 10.1038/s41586-020-2012-7.
21 Xu X., Chen P., Wang J., Feng J., Zhou H., Li X., et al. Evolution of the novel coronavirus from the ongoing Wuhan outbreak and modeling of its spike protein for risk of human transmission. Science China Life Sciences, 2020, 63(3):457-460.
22 Wan Y., Shang J., Graham R., Baric R.S., Li F. Receptor recognition by novel coronavirus from Wuhan: an analysis based on decade-long structural studies of SARS. Journal Virol, 2020, 94(7): e00127-20. doi: 10.1128/JVI.00127-20.
23 Wu A., Peng Y., Huang B., Ding X., Wang X., Niu P., et al. Genome composition and divergence of the novel coronavirus (2019-nCoV) originating in China. Cell Host Microbe, 2020, 27(3):325-328. doi: 10.1016/j.chom.2020.02.001.
24 Lu R., Zhao X., Li J., Niu P., Yang B., Wu H., et al. Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet, 2020, 395(10224):565-574.
25 Chen Y., Liu Q., Guo D. Emerging coronaviruses: genome structure, replication, and pathogenesis. J Med Virol, 2020, 92(4):418-423. doi: 10.1002/jmv.25681.
26 Hui D.S., Azhar E., Madani T.A., Ntoumi F., Kock R., Dar O., et al. The continuing 2019-nCoV epidemic threat of novel coronaviruses to global health-The latest 2019 novel coronavirus outbreak in Wuhan, China. International Journal of Infectious Diseases, 2020, 91:264-266.
27 SARS and MERS: recent insights into emerging coronaviruses (mg-labmanager.s3.amazonaws.com/assets/articleNo/22279/iImg/41328/apr9-2020-ibs-1-sars-cov-2-attachment.jpg) MeH http://uidemiz.kz/info/enter.html
28 Gralinski L.E., Menachery V.D. Return of the coronavirus: 2019-nCoV. Viruses, 2020, 12(2): 135. doi: 10.3390/v12020135.
29 Jayawardena R., Sooriyaarachchi P., Chourdakis M., Jeewandara C., Ranasinghe,P Enhancing immunity in viral infections, with special emphasis on COVID-19: A review. Diabetes & Metabolic Syndrome, 2020, 14:367-382.
30 Wu D., Lewis E.D., Pae M., Meydani S.N. Nutritional modulation of immune function: analysis of evidence, mechanisms, and clinical relevance. Frontiers in Immunology, 2019, 9:3160.
31 Gombart A.F., Pierre A., Maggini S. A Review of micronutrients and the immune systemworking in harmony to reduce the risk of infection. Nutrients, 2020, 12:236.
32 Al-Hatim R.R., Al-Rikabi A.K., Ghadban A.K. The Physico-chemical properties of bovine and buffalo whey proteins milk by using ultrafiltration membrane Technology. Basrah Journal of Agricultural Sciences, 2020, 33:122-134.
33 Claeys W.L., Cardoen S., Daube G., De Block J., Dewettinck K., Dierick K., Vandenplas Y. Raw or heated cow milk consumption: Review of risks and benefits. Food Control, 2013, 31:251-262.
34 Loss G., Depner M., Ulfman L.H., Van Neerven R.J., Hose A.J., Genuneit J., Weber J. Consumption of unprocessed cow's milk protects infants from common respiratory infections. Journal of Allergy and Clinical Immunology, 2015, 135:56-62.
35 Legrand D., Mazurier J. A critical review of the roles of host lactoferrin in immunity. Biometals, 2010, 23:365-376.
36 Lepanto M.S., Rosa L., Paesano R., Valenti P., Cutone A. Lactoferrin in aseptic and septic inflammation. Molecules, 2019, 24:1323.
37 Borzenkova N.V., Balabushevich N.G., Larionova N.I., Lactoferrin: physicochemical properties, biological functions, delivery systems, drugs and biological additives (review). Biopharmaceutical journal, 2010, 2(3):3-19.
38 Baker H.M., Baker E.N. Lactoferrin and iron: structural and dynamic aspects of binding and release. BioMetals, 2004, 17:209-216.
39 Legrand D., Pierce A., Elass E., Carpentier M., Mariller C., Mazurier J. Lactoferrin structure and functions. Adv. Exp. Med. Biol, 2008, 606:163-194.
40 Taylor S., Brock J., Kruger C., Berner T., Murphy M. Safety determination for the use of bovine milk-derived lactoferrin as a component of an antimicrobial beef carcass spray. Regulatory Toxicology and Pharmacology, 2004, 39:12-24.
41 Gonzalez-Chavez S.A., Arevalo-Gallegos S., Rascon Cruz Q. Lactoferrin: structure, function and applications. International Journal of Antimicrobial Agents, 2009, 33:301-308.
42 La O A.A. Isolation and structure-functional characterization of human colostral lactoferrin Biotecnol. Aplicada, 2000, 17:177-182.
43 Baker E.N., Baker H.M. A structural framework for understanding the multifunctional character of lactoferrin. Biochimie, 2009, 91:3-10.
44 Sharma S., Sinha M., Kaushik S., Kaur P., Singh T.P. C-Lobe of Lactoferrin: The Whole Story of the Half-Molecule. Review Article. Biochemistry Research International, 2013, 2013(271641): 1-8.
45 Hu F., Pan F., Sawano Y., Makino T., Kakehi Y., Komiyama M., Kawakami H., Tanokura M. Studies of the structure of multiferric ion-bound lactoferrin: A new antianemic edible material. Int. Dairy J., 2008, 18:1051-1056. doi: 10.1016/j.idairyj.2008.05.003.
46 Sorensen M., Sorensen S. Compte rendu des Travaux du Laboratoire de Carlsberg. The Proteins in Whey, 1939, 83:432.
47 Moore S.A., Anderson B.F., Groom C.R., Haridas M., Baker E.N. Three-dimensional structure of diferric bovine lactoferrin at 2.8 Á resolution. Journal of Molecular Biology, 1997, 274:222-236.
48 Conesa C., Sánchez L., Rota C., Pérez M.D., Calvo M., Farnaud S., Evans R.W. Isolation of lactoferrin from milk of different species: calorimetric and antimicrobial studies. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 2008, 150:131-139.
49 Okubo K., Kamiya M., Urano Y., Nishi H., Herter J.M., Mayadas T., Kurosawa M. Lactoferrin suppresses neutrophil extracellular traps release in inflammation. EBioMedicine, 2016, 10:204-215.
50 Iglesias-Figueroa B.F., Espinoza-Sánchez E.A., Siqueiros-Cendón T.S., Rascón-Cruz Q. Lactoferrin as a nutraceutical protein from milk, an overview. International Dairy Journal, 2019, 89:3741.
51 Cheng J.B., Wang J.Q., Bu D.P., Liu G.L., Zhang C.G., Wei H.Y., Zhou L.Y., Wang J.Z. Factors affecting the lactoferrin concentration in bovine milk. Journal of Dairy Science, 2008, 91:970-976.
52 Stelwagen K., Carpenter E., Haigh B., Hodgkinson A., Wheeler T.T. Immune components of bovine colostrum and milk. Journal of Animal Science, 2009, 87:3-9.
53 Al-Majali A.M., Ismail Z.B., Al-Hami Y., Nour A.Y. Lactoferrin concentration in milk from camels (Camelus dromedarius) with and without subclinical mastitis. International Journal of Applied Research in Veterinary Medicine, 2007, 5:120.
54 El-Hatmi H., Girardet J., Gaillard J., Yahyaoui M.H., Attia H. Characterization of whey proteins of camel (Camelus dromedarius) milk and colostrum. Small Ruminant Research, 2007, 70:267-271.
55 Furmanski P., Li Z.P., Fortuna M.B., Swamy C.V., Das M.R. Multiple molecular forms of human lactoferrin. Identification of a class of lactoferrins that possess ribonuclease activity and lack iron-binding capacity. Journal of Experimental Medicine, 1989, 170:415-429.
56 Berlutti F., Pantanella F., Natalizi T., Frioni A., Paesano R., Polimeni A., Valenti P. Antiviral properties of lactoferrin- A natural immunity molecule. Molecules, 2011, 16:6992-7018.
57 Anghel L. Lactoferrin: analysis of the structure profile. Chemistry Journal of Moldova, 2014, 9:99-106.
58 Gao C.H., Dong H.L., Tai L., Gao X.M. Lactoferrin-containing immunocomplexes drive the conversion of human macrophages from M2-into M1- like phenotype. Frontiers in Immunology, 2018, 9:37.
59 Rawat P., Kumar S., Sheokand N., Raje C.I., Raje M. The multifunctional glycolytic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a novel macrophage lactoferrin receptor. Biochemistry and Cell Biology, 2012, 90:329-338.
60 Takayama Y., Aoki R., Uchida R., Tajima A., Aoki Yoshida A. Role of CXC chemokine receptor type 4 as a lactoferrin receptor. Biochemistry and Cell Biology, 2017, 95:57-63.
61 Valenti P., Antonini G. Lactoferrin: an important host defence against microbial and viral attack. Cellular and Molecular Life Sciences, 2005, 62:2576-2587.
62 Shin K., Wakabayashi H., Yamauchi K., Yaeshima T., Iwatsuki K. Recombinant human intelectin binds bovine lactoferrin and its peptides. Biological and Pharmaceutical Bulletin, 2008, 31:16051608.
63 Suzuki Y.A., Lopez V., Lonnerdal B. Lactoferrin. Cellular and Molecular Life Sciences, 2005, 62:2560.
64 Kell D.B., Heyden E.L., Pretorius E. The Biology of Lactoferrin, an iron-binding protein that can help defend against viruses and bacteria. Frontiers in Immunology, 2020, 11:1221.
65 Milewska A., Zarebski M., Nowak P., Stozek K., Potempa J., Pyrc K. Human coronavirus NL63 utilizes heparan sulfate proteoglycans for attachment to target cells. Journal of Virology, 2014, 88:1322113230.
66 Azhar J., Mohammadabadi T., Babar M.E., Hussain T. Milk Lactoferrin: A Probable Immunological Agent Against SARS-CoV-2: A Review. Basrah Journal of Agricultural Sciences, 2020, 33(2):138-146.
67 Puddu P., Valenti P., Gessani S. Immunomodulatory effects of lactoferrin on antigen presenting cells. Biochimie, 2009, 91:11-18.
68 Britigan B.E., Lewis T.S., Waldschmidt M., McCormick M.L., Krieg A.M. Lactoferrin binds CpG-containing oligonucleotides and inhibits their immunostimulatory effects on human B cells. The Journal of Immunology, 2001, 167:2921-2928.
69 Legrand D., Elass E., Carpentier M., Mazurier J. Interactions of lactoferrin with cells involved in immune function. Biochemistry and Cell Biology, 2006, 84:282-290.
70 Queiroz V.A.O., Assis A.M.O., Júnior H.C.R. Protective effect of human lactoferrin in the gastrointestinal tract. Revista Paulista de Pediatria, 2013, 31:90-95.
71 Ishii K., Takamura N., Shinohara M. Longterm follow-up of chronic hepatitis C patients treated with oral lactoferrin for 12 months. Hepatology Research, 2003, 25:226-233.
72 Embleton N.D., Berrington J.E., Chris W.M., Cummings S.S. Lactoferrin: Antimicrobial activity and therapeutic potential. Seminars in Fetal & Neonatal Medicine, 2013, 18:143-149.
73 Mehta P., Mc Auley D.F., Brown M., Sanchez E., Tattersall R.S., Manson J.J. Across Specialty Collaboration, U. COVID-19: Consider cytokine storm syndromes and immunosuppression. The Lancet, 2020,395:1033-1034.
М.Х. НАРМУРАТОВА1, А. БАЙДУЛЛАЕВА1, А.Е. МУРАТБЕКОВА1, Д.М. МАЗБАЕВА1,
Ж.Б. НАРМУРАТОВА12* 1 Казахский национальный университет им. аль-Фараби, Алматы, Казахстан 2Satbayev University, Алматы, Казахстан *e-mail: [email protected]
ОПИСАНИЕ СВОЙСТВА ЛАКТОФЕРРИНА МОЛОКА КАК
ИММУНОМОДУЛЯТОРА ПРОТИВ ВОЗБУДИТЕЛЯ КОРОНОВИРУСА
Аннотация
Недавнее появление нового коронавируса (2019 - nCoV), который вызвал вспышку необычной вирусной пневмонии у пациентов в Ухане, центральном городе Китая, является еще одним предупреждением о риске COV для здоровья населения. В условиях нынешней пандемии COVID-19, все больше внимания уделяется борьбе и профилактике заболеваний на основе многих противовирусных пищевых добавок. Лактоферрин является одной из естественных пищевых добавок, содержащихся в молоке домашних животных, и обладает иммуномодулирующим свойством из-за его способности удерживать железо и способности связываться с множеством клеточных рецепторов. Противовирусная способность лактоферрина была оценена в отношении
59
MHorux BupycoB, BKnronaa SARS-CoV, kotophh tccho cBa3aH c SARS-CoV-2 (Bo3ÖygHTenb COVID-19). HeoGxoguMo npoBecTH cneцнanbннe uccnegoBaHua noтeнцнana LF npoTHB SARS-CoV-2, nocKonbKy oh Mo«eT npegoTBpa^aTb unu npenaTcTBoBaTb 3apa«eHuro KneToK SARS-CoV-2 H3-3a ÖKonorKHecKoM aKTMBHocTK LF b oraomeHuu npoTKBoBupycHoro KMMyHMTeTa. mh HageeMca, hto ganbHeMmue uccnegoBaHua no o^HKe ^apMaKonorunecKoro э$$eктa naKTo^eppma npoTuB SARS-CoV-2 nogTBepgaT ero ponb b GopbGe c COVID-19.
KnroneBbie cnQBa: naKTo^eppuH, SARS-CoV-2, COVID-19, uMMyHoMogyn^ua.
IRSTI: 619:630:.5767.8
M.KH. NARMURATOVA1, A. BAYDULLAEVA1, A.E. MURATBEKOVA1, DM. MAZBAYEVA1, ZH.B. NARMURATOVA12* 1Al-Farabi Kazakh National University, Almaty, Kazakhstan 2Satbayev University, Almaty, Kazakhstan *e-mail: [email protected]
DESCRIPTION OF THE PROPERTIES OF MILK LACTOFERRIN AS AN IMMUNOMODULATOR AGAINST THE CORONOVIRUS CAUSES
doi: 10.53729/MV-AS.2023.01.03
Abstract
A recent of a novel coronavirus due to the emergence of a new coronavirus (2019-nCoV) in the Wuhan, central China caused by the development of specific viral pneumonia in patients was a significant public health concern. During the current COVID-19 pandemic, much attention is being paid to the fight and prevention of the disease on the basis of many dietary supplements. Lactoferrin is one of the natural nutritional supplement found in mammalian milk and has immunomodulatory properties based on its ability to bind iron and bind to many cell receptors. lactoferrin has been showed the antiviral activity against SARS-CoV and other SARS-CoV-2 related viruses (the causative agent of CoVID-19). A special research is needed to study the anti-SARS-CoV-2 ability of lactoferrin. Since lactoferrin possesses biological activity against antiviral immunity, lactoferrin may inhibit SARS-CoV-2 cell infection in the host cells. We are optimistic that further studies assessing the pharmacological effects of lactoferrin against SARS-CoV-2 will amplify its role in combating COVID-19.
Keywords: lactoferrin, SARS-CoV-2, COVID-19, immunomodulation.
A virus is a body consisting of genetic material and several proteins. A pathogen capable of reproduction by penetration into a living organism. Coronavirus (CoV) is a type of virus belonging to the Coronaviridae family of the Kingdom of Virus, formed by a combination of the words corona (crown) and viridae (virus). CoV-affects the respiratory tract, gastrointestinal tract, liver and central nervous system of humans, domestic animals, birds, bats, mice and many other wild animals [1-3]. Severe Acute Respiratory Syndrome (SARS) - is an infectious and potentially fatal respiratory disease. SARS is the result of infection with a coronavirus, which scientists have called the SARS-related coronavirus (SARS-CoV). In 2002-2003, SARS spread to 33 countries on 5 continents, as a result of which more than 8000 people became infected and 700 died [4-6], and in 2012 more than 2,428 people became infected with respiratory syndrome (MERS-Middle East respiratory syndrome) in the Middle East, 838 people died and were under strict control. Like the outbreak of this epidemic, the newly emerged CoV showed the presence of a malignant epidemic in terms of the possibility of rapid transmission from animals to humans and from human to human [7-8]. In 2019, an outbreak of pneumonia, unknown to the population, which occurred in mid-December at the Huanan Animal and seafood market in Wuhan, which is part of Hubei Province, located in central China, attracted the attention of the whole world. As a result of a strict sequence and etiological studies in Chinese scientific laboratories, a new coronavirus (novel coronavirus (nCoV)) was identified as the causative agent of unknown pneumonia (http://virological.org/ and
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https://www.gisaid.org/). After that, Chinese scientists named a new type of coronavirus-SARS-CoV-2. It was found that its genetic structure is 70% similar to the SARS-CoV virus, which causes severe acute respiratory syndrome. On January 12, 2020, the World Health Organization temporarily named the new virus the 2019 new coronavirus (2019 - nCoV) [9]. The main route of transmission of SARS-CoV-2 can occur through the external surface of objects, in particular, at the moment when an infected person coughs or massages the face, eyes, nose with the part of the body that the infected person touches [10]. However, it is unknown how long the virus will live in these places. Thus, the virus enters the body, multiplies and spreads to other organs. The main damaging forms are the intestine, spleen and the most dangerous damaging organ of the lungs. People infected with the virus have mild and severe clinical manifestations of dry cough, fever, shortness of breath, bilateral pneumonia and other symptoms, including sore throat, diarrhea and vomiting [10]. Sick patients may be in close contact with infected people and respiratory droplets [11]. A variety of antiviral treatments are offered. However, the human testing period may last for months or a year [12]. The current method of combating the pandemic is isolation, personal hygiene measures and a healthy diet.
The emergence and outbreaks of new CoV species have shown that this is a global malignant epidemic that is dangerous to health. In the future, due to climate change and ecology, as well as the strengthening of human relations with animals, a dangerous epidemic may flare up again. Thus, there was a need for immediate therapy and the development of vaccines against CoV. We hope that the data provided in the article will contribute to the prevention and protection from the new coronavirus epidemic, which has turned it into a global pandemic.
The path ofpenetration of the coronavirus into the cell. The penetration of coronavirus into a human cell consists of the following stages. 1. A virus that has entered the body with the help of the organs of the nose, mouth or eyes of a person is directed to the protein receptor of angiotensin converting enzyme 2 (ACE2) (Figure 1). ACE2 is a metallopeptidase, one of the important functional receptors of SARS-CoV-2. The angiotensin converting enzyme receptor 2 is located on the surface of cells that make up some organs, in particular, the mucous membrane of the mouth and nose, lungs, stomach, small intestine, colon, lymph nodes, thymus gland, bone marrow, liver, spleen, kidneys and brain. The ACE2 receptor is very often found on the surface of the epithelial cells of the lung alveoli [13].
Figure 1 - The binding of a coronavirus cell and its binding to the ACE 2 receptor is shown [27]
As shown in the first figure, after the coronavirus virus recognizes the angiotensin converting enzyme receptor 2 from the cell surface, the specified receptor and the Spike protein (S) firmly
61
bind to each other as a "key" and "lock". As shown in crystallographic studies, the S1 segment (318-510 amino acid residues) is a region that binds to receptors important for the angiotensin converting enzyme receptor 2 [13-15]. Under the influence of a strong bond, the function of the ACE 2 receptor involved in the regulation of blood pressure is disrupted. As a result, with the help of the angiotensin converting enzyme receptor 2, the SARS-CoV-2 virus penetrates into the cell of the human body [16]. Once inside the cell, the coronavirus virus releases the entire structural protein layer surrounding it from the outside [15].
In the above sequence, SARS-CoV-2 itself or only genomic RNA enters the cytoplasm. Meanwhile, the RNA genome of the SARS-CoV virus has a length of about 30,000 nucleotides [17]. At the next stage of virus penetration into the cytoplasm, the stage of translation of the proteins responsible for the virus, RNA-a protein that has penetrated into the cytoplasm, begins. The process of doubling occurs based on the process of replication of genomic RNA penetrating the cytoplasm. Before replicating RNA, SARS-CoV-2 needs important proteins that replicate RNA. The formation of these proteins using viral RNA as a source of material is called translation. During the implementation of this process, the SARS-CoV-2 virus parasitizes the host cell (Figure 2).
Figure 2 - Diagram of the pathway of the SARS-CoV-2 virus into the cell [27]
The third stage is the replication of the virus RNA. It works in the process of viral RNA replication after the formation of proteins responsible for the replication of secondary RNA. Mentioned, SARS-CoV-2-positive RNAs are among the viruses. After the replication stage is completed, negative RNA is formed from positive RNA. After that, at the fourth stage, the formation of structural particles of the virus begins. Particles of the structure of new viruses begin to form from the negative RNA of SARS-CoV-2. Using negative RNA as a source of material,
several mRNAs are formed. As a result, structural proteins of the virus are formed from mRNA, such as glycoprotein s-protein, membrane protein (M), small protein (E), nucleocapsid (N). At the fifth stage, after structural proteins are formed inside the EPT, proteins and RNA pass into the Golgi apparatus. Inside the Golgi apparatus, structural proteins and positive RNA are combined into a complete virus, and the visicle is placed inside the "bubbles". At the sixth stage, the fully accumulated virus inside the vesicle begins to exit the cell during exocytosis. A fully developed virus attacks other cells [19-28].
The body's resistance to the virus is closely related to the system of healthy nutrition. Foods enriched with natural biologically active substances can reduce the risk of viral infections in the body [29]. In improving immunity, such components in food increase the activity of ViT cells and participate in their proliferation, induction and modulation of the innate and adaptive immune response [30-31]. Based on the above data, optimal nutrition is the only sustainable way for the immune system to resist COVID-19.
Among food products, milk and dairy products are useful for the immune system with their valuable proteins [32]. Epidemiological studies have shown that regular consumption of cow, mare and camel milk is characterized by a low prevalence of bacterial and viral infections in humans [33-34]. One of the important components of milk is lactoferrin (LF), a multifunctional protein belonging to the genus of transferrins.
The immunoprotective and anti-inflammatory properties of the lactoferrin protein, which provide protection against respiratory viruses such as SARS-CoV-2, have been shown in a number of scientific articles [9;15;35]. To study the potential of LF in immune protection against COVID-19, it is necessary to know its biology, structure, binding of membrane receptors, immunomodulatory and antiviral mechanisms, as well as its sources. The article discusses the preventive, therapeutic, immunoprotective and mechanism of action of lactoferrin against viruses, and also discusses the role of lactoferrin protein as an additional method of treatment of COVID-19.
Structure and physico-chemical properties of lactoferrin. The LF protein is a heme-free iron-binding glycoprotein belonging to the transferrin (TF) group. It was first isolated from cow's milk in 1939, and from mother's milk in 1960. The amino acid sequence of LF was determined in 10 animal species (human, cow, mouse, horse, pig, goat, sheep, buffalo and camel) [36-37]. The LF protein molecule consists of a single polypeptide chain consisting of approximately 700 amino acid residues. The molecular weight is ~ 76-80 kDa. The similarity of the primary structure of the human and mouse LF protein is 70%, human and cow — 69%, cow and mouse — 63% [38]. The primary structure of human LF protein has a high degree of similarity (~ 59%) with human serum TF. Transcription of the LF gene under the influence of alternative promoters - P1 and P2 - leads to the formation of two products: LF mRNA and delta-LF (A - LF) [39]. A-LF does not perform functions due to the absence of an N-terminal signal sequence [40]. The isoelectric point of the human LF in the literature is 8.0-8.5 [41]; ranges from 8.7 to 9.7 [42].
The polypeptide chain of the DA protein consists of two homologous globular fractions C and T. The similarity of the amino acid composition in the two fractions is about 37%. Fraction N forms the N-end of the polypeptide chain (1-332 amino acid residues), fraction C forms the C-end (345-691 amino acid residues). They are connected by a short alpha helix (amino acid 333-344), this compound gives the molecule an additional elastic property [37]. Each lobe has an ellipsoidal shape with dimensions of the order of 55*35*35 A. The protein molecule is not symmetrical, since its parts are rotated at an angle of ~ 150° to each other and shifted by 25 A. Each lobe, in turn, consists of two domains with a very similar secondary structure [37; 43]. The molecule consists of ~ 43% a-helix and ~ 27% P-helix. The protein structure has 16 disulfide bonds, 6 pairs of which are equal in both lobes, and the remaining 4 pairs are located in the C-lobes. The general scheme of the bovine lactoferrin protein molecule is shown in the third figure.
Figure 3 - Diagram of the bovine lactoferrin protein molecule Domains N1 and N2 are marked in yellow and pink, respectively, and domains C1 and C2 are green and blue, respectively, and the interconnected spiral between the petals is orange, and two iron atoms are
shown by red spheres [44]
LF exists in two different forms: apo (an iron-unsaturated protein) and holo (with Fe3+ in the active center). The LF protein molecule is able to reversibly bind to two Fe3+ ions. The deeper region between the domains (N1, N2 and C1, C2) in each lobe contains iron binding sites of ~42 A in size. Each iron atom is coordinated with four protein ligands: Tyr-92 and Tyr-192 with two oxygen atoms in phenolate ions (Tyr - 435 and Tyr-528 at the C-terminus, respectively), His - 253 (His - 597) with a nitrogen atom N2 in imidazole and Asp-60 (Asp-395) with carboxylic oxygen. Each iron atom has an octahedral environment, but four protein ligands occupy only four positions out of six. According to studies, the remaining two positions contain CO32- or HCO3- anions [37; 43].
The scheme of binding of LF to iron is shown (Figure 4). The iron atom is represented by a red sphere, and the interacting amino acid residues of LF are yellow. The residue numbers correspond to the N-terminus, and the amino acid residues corresponding to the C-terminus are indicated in parentheses [44].
The anion binds to the positively charged N-terminal of the peptide and the Arg121 radical. In mutagenesis experiments, it has been proven that the replacement of any 4 residues in the active center leads to an immediate deterioration in the ability of iron binding. Mutation of the Arg-121 residue leads to the same effect [38; 43].
Iron binds strongly and irreversibly (Kd~10-20 M-1) to the LF protein. The LF protein is able to bind iron even with a competing ligand (for example, citrate) at pH 3.0, while other TF proteins secrete iron at pH ~5.5 [37]. The different properties of LF and TF are determined by the harmonious union of the two lobes of LF [38]. Binding of iron to the C-fraction of DA additionally stabilizes its binding (iron to protein) in the T-fraction. An important role here is played by the alpha helix at the C-end, which interacts with the N-lobe. The absence of this phenomenon in TV is explained by the peculiarity of the structure of the peptide connecting the two lobes of LF. In all described LFS, this peptide forms an alpha helix, whereas in TF it has a weak, straight, disordered structure. The strength of the alpha helix ensures tight binding of the two lobes and stabilizes the binding of iron to the N-lobe. As a result, this affects the release of iron (from the LF) and shifts the pH value towards the lower limit. The presence of lysine residues - Lys-206 and Lys-296 - in the ATP molecule may be the reason for the difference in the functions of LF and TF. These two residues form a unique hydrogen bond. Arg-210 and Lys-301 of the human DA protein are replaced by this pair of residues. However, the proteins of cows, buffaloes, horses and camels
contain two lysine residues similar to the position in NA - Lis-2010 and Ls-301. However, no connection is formed between these two residues and, accordingly, protein specificity is not observed [37-38].
Figure 4 - Scheme of iron binding by lactoferrin [26]
The binding and release of iron with protein leads to structural changes in the LF protein [37]. The LF protein binds to iron in an open structure: first of all, it binds to the anion, which leads to the displacement of ligands. Then iron completely binds to the LF protein molecule, and then LF passes into a very compact structural form, that is, a closed structural form. The apo form of the LF protein can bind to other metal ions, usually with strongly positively charged ion uoHgap (Cr3+, Co3+, Mn3+, Al3+, Ga3+, Cu2+, Zn2+, Cd2+, Ni2+, lanthanide ions) [37-38]. The mentioned metal ions bind to the LF protein through amino acids that bind Fe3+. In addition, it has been shown that the LF protein can bind up to 70 Fe3+ ions using sections of the peptide chain [45]. As a result, a substance consisting of 15-16 LF protein molecules is formed. This substance has a very high stability compared to the native protein. The stability increase is based on the electrostatic coupling between Fe3+and HCO-3 ions present in the composition of various LF protein molecules in this substance [37].
The LF protein is a globular glycoprotein [39]. The carbohydrate fragment forms a glycosidic bond with the protein via asparagine amide nitrogen (Asn-137 and Asn-490). The number and location of glycoside bonds in the LF varies depending on the type of animal [37; 39]. Many LF functions are determined by its unevenly distributed surface charge. Three positively charged regions can be distinguished: N-at the end (residues 1-5), in the first alpha helix (residues 12-31) and between the two lobes. The GRRRR signal sequence at the N-end of the human LF ensures the penetration of this protein into the nucleus. Thus, it acts as a transcription factor. The above signal scheme is characteristic only for human LF, it is absent in other animals [37].
Sources of lactoferrin. The LF protein is secreted by epithelial cells of the mucous membrane of various mammals [46-50]. LF protein comes from all exocrine iron juices: lacrimal (2 mg/ml [41; 46-50] or 0.4 mg/ml), saliva (0.013 mg/ml), nasal and bronchial, bile juices (0.0042 mg/ml), pancreatitis juices, seminal fluid (0.518 mg/ml), urine (0.00005 mg/ml), sweat (0.0025 mg/ml). LF is contained in very large quantities in milk (1.28 mg/ml) and colostrum (7 mg/ml or 3.2 mg/ml) [37; 51]. The most common protein after casein in milk. The concentration of LF in cow's milk varies from 31.78 to 485.63 p,g. mL-1 depending on the lactation period, the breed of cows [51], and its concentration in colostrum is 1-5 mg / ml. In addition, the concentration of lactoferrin in camel milk is 20-2100 p,g. mL-1 [52-53] [30]. Studies show that camel milk lactoferrin varies from 0.02 to 7.28 p,g. mL-1 in regular milk, but the maximum amount of lactoferrin is 2.3 g.L-1
approximately 48 hours after calving. is the value [54]. Since the biological activity of bovine and human LF is similar, this allows the use of animal milk as an available source of lactoferrin protein. In the mammary glands, the secretion of LF protein (transcription and translation) is controlled by prolactin, and the expression of LF protein in the genital tract is induced by the steroid hormone estrogen. In the hematopoietic system, LF is expressed (synthesized) in neutrophils that develop at the stage of maturation of myelocytes [37]. Accumulates in secondary neutrophil granules. The protein content in them is 15 15 mcg/106 [40]. In addition, LF was detected in blood (0.001 mg/ml) and amniotic fluid (0.006 mg/ml). The normal amount in the blood is about 1 mcg/ml, although with inflammation its amount can reach 200 mcg/ml [37].
Three different isoforms of lactoferrin are known, which include alpha-LF (LF-a), beta-LF (LF-P) and gamma-LF (LF-g). LF-a binds iron, but the other two isoforms, LF-P and LF-g, do not bind to iron [55-57].
Immunomodulatory effect of lactoferrin. The mechanism of binding of the LF protein to membrane receptors indicates its biological activity. LF binds to the following receptors: TLR2, TLR4 [58], CD14 [59], cytokine receptors [60] and Intelectin-1 [61]. It has been suggested that all these receptors are found in many types of cells and tissues, including lymphocytes and intestinal epithelial cells [62]. The ability of the LF protein to bind to receptors is important for increasing its antiviral immunity and the body's defense mechanism. The LF protein performs its immunomodulatory activity by competing with infectious molecules, thereby suppressing particle fusion [63]. The specificity of the LF protein lies in the fact that heparan sulfate binds to proteoglycans (HSPGs), the receptor for attachment and introduction of SARS-CoV and human coronavirus NL63 into the cell [6; 64]. SARS-CoV-2 uses ACE2 as its functional receptor, but can bind to heparan sulfate proteoglycans (HSPG), since SARS-CoV has been found to bind both receptors, however, studies of the use of HSPG for SARS-CoV-2 have not been fully proven. Epithelial cells are considered the first physical barrier preventing the penetration of harmful substances, and play an important role in innate immunity [65].
The LF protein plays an important role in the immune system and the defense system of infection and inflammation [61]. Some of its immunomodulatory effects are based on lipopolysaccharide complexes (LPS). The LF protein binds to the LPS associated with the virus, thereby preventing the virus from entering the cell, but when the virus enters the cell, it suppresses the reproduction of the virus, stimulating killer cells such as granulocytes and macrophages [65]. The LF protein participates in the regulation of cytokine/chemokine and peroxide production [6667], activation and proliferation of immune cells, in particular macrophages, neutrophils, basophils, eosinophils, mastocytes and dendritic cells [35]. The phagocytic capacity of cells is modulated by the recognition of certain LF protein binding sites [68].
The LF protein delivered to the nucleus binds to DNA and activates various signaling pathways [41; 69]. Tumor necrosis of LF was detected using interferongamma, Alpha factor and inhibitory activity of proinflammatory cytokines such as interleukin (IL) -1, IL-2 and IL-6. In addition, at the cellular level, LF enhances the absorption of polymorphic nuclear blood cells and stimulates the myelopoietic process [41]. Also, in chronic diseases, LF increases the profile of Th1 cytokines in peripheral blood [70].
The lactoferricin peptide obtained as a result of the degradation of LF limits the onset of the inflammatory process, increases the production of IL-10, thereby stimulating Th2 (antiinflammatory) activity. LF interference occurs as a result of the expression of the fibroblast gene, modulates protein production and changes the extracellular matrix, thereby increasing the mobility of immune cells [71].
Antiviral effect of lactoferrin protein. The LF protein has antiviral properties that suppress most RNA and DNA viruses infecting humans and animals. There are two types of antiviral action of the LF protein. Firstly, it can inhibit the binding stage of the virus to the host cell, such as herpes, hepatitis B, human cytomegalovirus, adeno-, rota- and polioviruses. Secondly, it suppresses the process of virus replication in affected cells (hepatitis C and G, AIDS). In the early stages of the damage process, the protein can have an antiviral effect [37].
The inhibition of the LF protein of viral infection is explained by the effect that prevents the binding of the virus to the host cell, presumably because molecules located on the cell surface can participate in it. Glucosaminglycones, mainly heparan sulfates, are very strong anions present on the surface of mammalian cells because they are characterized by a high degree of sulfation. As a result of the presence of a very large amount of negative charge, glucosamine glycones provide binding to cations, proteins, enzymes, cytokines, chemokines, lipoproteins, as well as to various pathogens and viruses. According to a widespread and studied mechanism, the LF protein binds to heparan sulfate, preventing the primary interaction of the virus with the cell and protecting it from damage [41].
Numerous studies, including an in vitro study, have shown that of all the proteins in human blood and milk, only LF protein has a very high effect against AIDS. This phenomenon is based on the properties of inhibiting virus replication inside the host cell [37]. According to the results of other studies, the apo-form of the LF protein binds to parts of the rotavirus, preventing hemaagglutination and interaction of the virus with cellular receptors [68]. This antiviral activity of the LF protein decreases with increasing saturation of the protein with Fe3+, Fe2+ ions, as well as divalent metal ions such as Mg2+ and Zn2+. According to the results of recent studies (2009), direct binding of LF to structural proteins III and III A of the virus contributes to the neutralization of adenovirus [69]. The LF protein also blocks the internalization of certain viruses in the cell. This includes type I polyvirus, type I herpes simplex and ATC cytomegalovirus [36].
The LF protein is very important as a protective molecule of the host cell, and its physiological activity can be anti-inflammatory, antibacterial, antiviral, antioxidant, immunomodulatory, anticarcinogenic, antiprotozoal and antifungal [36]. According to studies, the ability of the LF protein to retain iron is also effective for modulating the mobility of immune cells and suppressing the growth of pathogenic microorganisms [51].
Coronavirus and lactoferrin
During SARS-CoV infection, the immune response of the host cell (organism) against the virus begins. The innate immune response plays an important role in suppressing viral infection. It has been suggested that the LF protein has an effect on the activation of the innate immune response against the SARS-CoV virus [11]. LF protein has been shown to increase NK cell activity during SARS-CoV infection and stimulate neutrophil aggregation and adhesion. However, the biological activity of the LF protein has not been fully studied.
A
SARS CoV
Г у
HSPG ACE2 ^ j HSPG ACE2
Figure 5 - Model of SARS-CoV cell penetration and the protective role of lactoferrin in SARS-CoV
infection [15]
(A) HSPGs play an important role in the process of SARS-CoV penetration into the cell. HSPG binding sites allow primary binding between SARS-CoV and the host cell. The SARS-CoV virus attaches to the cell membrane by binding to HSPG and ACE2, looking for specific entry receptors (ACE2), thereby penetrating into the cell. (B) The LF protein blocks SARS-CoV
infection by binding to HSPG. The LF protein is deposited in hspg on the cell surface and prevents preliminary interaction and subsequent internal processes between the virus and host cells [15]
Viruses typically use common molecules on the cell membrane to facilitate entry into cells. These molecules, including heparan sulfate proteoglycans (HSPGs), help establish the first contact for penetration into the host cell by providing binding sites to the first virus on the cell surface [38]. It has been shown that the LF protein prevents the penetration of some viruses into the internal cells of the body by binding to HSPGs present in many cells [39].
This property of the LF protein protects the host cell or organism from viral infections. Based on these findings, another effect of the LF protein against SARS-CoV is predicted by its binding to the HSPGs -molecule, which is widespread in host cells. The above data show that during the penetration of the SARS pseudovirus into the cell, the ACE2 and HSPGs receptors on the cell surface play an important role (Figure 5). The LF protein can block SARS pseudovirus infection by binding to ASE2 and HSPGs, suggesting that it may play a protective role in the host cell's immune system against SARS-CoV attack.
Methods of combating the COVID-19 pandemic, in addition to compliance with restrictions and hygiene measures, still require comprehensive study, although antiviral drugs and vaccines have been discovered. The possibility of using LF protein as a dietary supplement against a wide range of viruses, including SARS CoV, has been studied. These research papers are interesting because they are close to SARS CoV-2, belonging to the same relative [9; 15]. The similarity of the SARS-CoV and SARS-CoV-2 sequences is 79%, and their receptor-binding domain structure is also very similar. In addition, the binding of LF protein to heparan sulfate proteoglycans on the cell surface (HSPGs) in mouse coronavirus, human coronavirus HCoV-NL63 [64] and SARS-CoV [15] suppresses the activity of the virus. But there are no proven studies of the effect of the LF protein on the penetration of SARS-CoV-2 into host cells [65]. In some patients, death from COVID-19 is associated not only with viral infection, but also with hyperinflammatory and cytokine disease syndrome, which leads to acute respiratory distress and subsequent death [72]. In severe cases of COVID-19, an increase in the level of cytokines and interleukin IL-6, tumor necrosis factor (TNFa) and ferritin is observed [65]. The LF protein can modulate the immune and inflammatory response against viral infection, so the LF protein can serve as a basis for further treatment of severe cases of COVID-19.
Conclusion
The LF protein in milk is effective against viral attacks as an important dietary supplement, binds to many viral particles or viral receptors and helps strengthen the immune system. In addition, the lactoferrin protein, which has special immunomodulatory, anti-inflammatory and antiviral properties, may have valuable potential as a preventive, preventive and complementary treatment for COVID-19, since it includes both viral infection and the immune response of the host cell. However, more research and development is needed regarding the lactoferrin protein dietary supplement for the SARS-CoV-2 virus.
References:
1 Wang L.F., Shi Z., Zhang S., Field H., Daszak P., Eaton B. Review of bats and SARS. Emerg InfectDis., 2006, 12(12): 1834-1840.
2 Ge X.Y., Li J.L., Yang X.L., et al. Isolation and characterization of a bat SARS-like coronavirus that uses the ACE2 receptor. Nature, 2013, 503(7477):535-538.
3 Chen Y, Guo D. Molecular mechanisms of coronavirus RNA capping and methylation. Virol Sin., 2016, 31(1):3-11.
4 Cui J., Li F., Shi ZL. Origin and evolution of pathogenic coronaviruses. Nat Rev Microbial., 2019, 17(3): 181-192.
5 Cauchemez S., Van Kerkhove M.D., Riley S., Donnelly C.A., Fraser C., Ferguson N.M. Transmission scenarios for Middle East respiratory syndrome coronavirus (MERS-CoV) and how to tell them apart. Euro Surveill., 2013, 18(24):20503.
6 Guan Y., Zheng BJ., He YQ., Liu XL., Zhuang ZX., et al. Isolation and characterization of
viruses related to the SARS Coronavirus from animals in southern China. Science, 2003, 302:276-278.
7 Rahman A., Sarkar A. Risk factors for fatal middle east respiratory syndrome Coronavirus infections in Saudi Arabia: analysis of the WHO Line List, 2013-2018. Am J Public Health, 2019, 109(9): 1288-1293.
8 Memish Z.A., Zumla A.I., Al-Hakeem R.F., Al-Rabeeah A.A., Stephens G.M. Family cluster of Middle East respiratory syndrome Coronavirus infections. N Engl. J Med, 2013, 368(26):2487-2494.
9 Chen Y., Liu Q., Guo D. Emerging coronaviruses: genome structure, replication, and pathogenesis. Journal of Medical Virology, 2020, 92:418-423.
10 Zhu N., Zhang D., Wang W., Li X., Yang B., Song J., Niu P. A novel coronavirus from patients with pneumonia in China, 2019. New England Journal of Medicine, 2020, 382:727-733.
11 Shereen M.A., Khan S., Kazmi A., Bashir N., Siddique R. COVID-19 infection: Origin, transmission, and characteristics of human coronaviruses. Journal of Advanced Research, 2020, 94:91-98.
12 Kuchler H., Cookson C., Neville S. The $2 bn race to find a vaccine. Financial Times, 2020, 7.
13 Du L., He Y., Zhou Y., Liu S., Zheng B., Jiang S. The Spike protein of SARS-CoV-a target for vaccine and therapeutic development. Nature review Microbiology, 2009, 7:226-236.
14 Chen J., Subbarao K. The Immunobiology of SARS. Annu Rev Immunol, 2007, 25:443-472.
15 Lang J., Yang N., Deng J., Liu K., Yang P., Zhang G., Jiang C. Inhibition of SARS pseudovirus cell entry by lactoferrin binding to heparan sulfate proteoglycans. PLoS one, 2011, 6: e23710.
16 Zhu N., Zhang D., Wang W., Li X., Yang B., Song J., Niu P. A novel coronavirus from patients with pneumonia in China, 2019. New England Journal of Medicine, 2020, 382:727-733.
17 Bartlam M., Yang H., Rao Z. Structural insights into SARS coronavirus proteins. Current Opinion in Structural Biology, 2005, 15:664-672.
18 Li F., Li W., Farzan M., Harrison S.C. Structure of SARS Coronavirus Spike Receptor-Binding Domain Complexed with Receptor. Science, 2005, 309:1864-1868.
19 Wu F., Zhao S., Yu B., Chen Y-M., Wang W., Song Z-G., et al. A new coronavirus associated with human respiratory disease in China. Nature, 2020, 579(7798):265-269. doi: 10.1038/s41586-020-2008-3.
20 Zhou P., Yang X., Wang X., Hu B., Zhang L., Zhang W., et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature, 2020, 579(7798):270-273. doi: 10.1038/s41586-020-2012-7.
21 Xu X., Chen P., Wang J., Feng J., Zhou H., Li X., et al. Evolution of the novel coronavirus from the ongoing Wuhan outbreak and modeling of its spike protein for risk of human transmission. Science China Life Sciences, 2020, 63(3):457-460.
22 Wan Y., Shang J., Graham R., Baric R.S., Li F. Receptor recognition by novel coronavirus from Wuhan: an analysis based on decade-long structural studies of SARS. Journal Virol, 2020, 94(7): e00127-20. doi: 10.1128/JVI.00127-20.
23 Wu A., Peng Y., Huang B., Ding X., Wang X., Niu P., et al. Genome composition and divergence of the novel coronavirus (2019-nCoV) originating in China. Cell Host Microbe, 2020, 27(3):325-328. doi: 10.1016/j.chom.2020.02.001.
24 Lu R., Zhao X., Li J., Niu P., Yang B., Wu H., et al. Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet, 2020, 395(10224):565-574.
25 Chen Y., Liu Q., Guo D. Emerging coronaviruses: genome structure, replication, and pathogenesis. J Med Virol, 2020, 92(4):418-423. doi: 10.1002/jmv.25681.
26 Hui D.S., Azhar E., Madani T.A., Ntoumi F., Kock R., Dar O., et al. The continuing 2019-nCoV epidemic threat of novel coronaviruses to global health-The latest 2019 novel coronavirus outbreak in Wuhan, China. International Journal of Infectious Diseases, 2020, 91:264-266.
27 SARS and MERS: recent insights into emerging coronaviruses (mg-labmanager.s3.amazonaws.com/assets/articleNo/22279/iImg/41328/apr9-2020-ibs-1-sars-cov-2-attachment.jpg) мен http ://uidemiz .kz/info/enter.html
28 Gralinski L.E., Menachery V.D. Return of the coronavirus: 2019-nCoV. Viruses, 2020, 12(2): 135. doi: 10.3390/v12020135.
29 Jayawardena R., Sooriyaarachchi P., Chourdakis M., Jeewandara C., Ranasinghe,P Enhancing immunity in viral infections, with special emphasis on COVID-19: A review. Diabetes & Metabolic Syndrome, 2020, 14:367-382.
30 Wu D., Lewis E.D., Pae M., Meydani S.N. Nutritional modulation of immune function: analysis
of evidence, mechanisms, and clinical relevance. Frontiers in Immunology, 2019, 9:3160.
31 Gombart A.F., Pierre A., Maggini S. A Review of micronutrients and the immune systemworking in harmony to reduce the risk of infection. Nutrients, 2020, 12:236.
32 Al-Hatim R.R., Al-Rikabi A.K., Ghadban A.K. The Physico-chemical properties of bovine and buffalo whey proteins milk by using ultrafiltration membrane Technology. Basrah Journal of Agricultural Sciences, 2020, 33:122-134.
33 Claeys W.L., Cardoen S., Daube G., De Block J., Dewettinck K., Dierick K., Vandenplas Y. Raw or heated cow milk consumption: Review of risks and benefits. Food Control, 2013, 31:251-262.
34 Loss G., Depner M., Ulfman L.H., Van Neerven R.J., Hose A.J., Genuneit J., Weber J. Consumption of unprocessed cow's milk protects infants from common respiratory infections. Journal of Allergy and Clinical Immunology, 2015, 135:56-62.
35 Legrand D., Mazurier J. A critical review of the roles of host lactoferrin in immunity. Biometals, 2010, 23:365-376.
36 Lepanto M.S., Rosa L., Paesano R., Valenti P., Cutone A. Lactoferrin in aseptic and septic inflammation. Molecules, 2019, 24:1323.
37 Борзенкова Н.В., Балабушевич Н.Г., Ларинова Н.И. Лактоферрин: физико-химические свойства, биологические функции, системы доставки, лекарственные препараты и биологически активные добавки. Биофармацевтический журнал, 2010, 2(3):3-19.
38 Baker H.M., Baker E.N. Lactoferrin and iron: structural and dynamic aspects of binding and release. BioMetals, 2004, 17:209-216.
39 Legrand D., Pierce A., Elass E., Carpentier M., Mariller C., Mazurier J. Lactoferrin structure and functions. Adv. Exp. Med. Biol, 2008, 606:163-194.
40 Taylor S., Brock J., Kruger C., Berner T., Murphy M. Safety determination for the use of bovine milk-derived lactoferrin as a component of an antimicrobial beef carcass spray. Regulatory Toxicology and Pharmacology, 2004, 39:12-24.
41 Gonzalez-Chavez S.A., Arevalo-Gallegos S., Rascon Cruz Q. Lactoferrin: structure, function and applications. International Journal of Antimicrobial Agents, 2009, 33:301-308.
42 La O A.A. Isolation and structure-functional characterization of human colostral lactoferrin Biotecnol. Aplicada, 2000, 17:177-182.
43 Baker E.N., Baker H.M. A structural framework for understanding the multifunctional character of lactoferrin. Biochimie, 2009, 91:3-10.
44 Sharma S., Sinha M., Kaushik S., Kaur P., Singh T.P. C-Lobe of Lactoferrin: The Whole Story of the Half-Molecule. Review Article. Biochemistry Research International, 2013, 2013(271641): 1-8.
45 Hu F., Pan F., Sawano Y., Makino T., Kakehi Y., Komiyama M., Kawakami H., Tanokura M. Studies of the structure of multiferric ion-bound lactoferrin: A new antianemic edible material. Int. Dairy J., 2008, 18:1051-1056. doi: 10.1016/j.idairyj.2008.05.003.
46 Sorensen M., Sorensen S. Compte rendu des Travaux du Laboratoire de Carlsberg. The Proteins in Whey, 1939, 83:432.
47 Moore S.A., Anderson B.F., Groom C.R., Haridas M., Baker E.N. Three-dimensional structure of diferric bovine lactoferrin at 2.8 Á resolution. Journal of Molecular Biology, 1997, 274:222-236.
48 Conesa C., Sánchez L., Rota C., Pérez M.D., Calvo M., Farnaud S., Evans R.W. Isolation of lactoferrin from milk of different species: calorimetric and antimicrobial studies. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 2008, 150:131-139.
49 Okubo K., Kamiya M., Urano Y., Nishi H., Herter J.M., Mayadas T., Kurosawa M. Lactoferrin suppresses neutrophil extracellular traps release in inflammation. EBioMedicine, 2016, 10:204-215.
50 Iglesias-Figueroa B.F., Espinoza-Sánchez E.A., Siqueiros-Cendón T.S., Rascón-Cruz Q. Lactoferrin as a nutraceutical protein from milk, an overview. International Dairy Journal, 2019, 89:3741.
51 Cheng J.B., Wang J.Q., Bu D.P., Liu G.L., Zhang C.G., Wei H.Y., Zhou L.Y., Wang J.Z. Factors affecting the lactoferrin concentration in bovine milk. Journal of Dairy Science, 2008, 91:970-976.
52 Stelwagen K., Carpenter E., Haigh B., Hodgkinson A., Wheeler T.T. Immune components of bovine colostrum and milk. Journal of Animal Science, 2009, 87:3-9.
53 Al-Majali A.M., Ismail Z.B., Al-Hami Y., Nour A.Y. Lactoferrin concentration in milk from camels (Camelus dromedarius) with and without subclinical mastitis. International Journal of Applied Research in Veterinary Medicine, 2007, 5:120.
54 El-Hatmi H., Girardet J., Gaillard J., Yahyaoui M.H., Attia H. Characterization of whey proteins
of camel (Camelus dromedarius) milk and colostrum. Small Ruminant Research, 2007, 70:267-271.
55 Furmanski P., Li Z.P., Fortuna M.B., Swamy C.V., Das M.R. Multiple molecular forms of human lactoferrin. Identification of a class of lactoferrins that possess ribonuclease activity and lack iron-binding capacity. Journal of Experimental Medicine, 1989, 170:415-429.
56 Berlutti F., Pantanella F., Natalizi T., Frioni A., Paesano R., Polimeni A., Valenti P. Antiviral properties of lactoferrin- A natural immunity molecule. Molecules, 2011, 16:6992-7018.
57 Anghel L. Lactoferrin: analysis of the structure profile. Chemistry Journal of Moldova, 2014, 9:99-106.
58 Gao C.H., Dong H.L., Tai L., Gao X.M. Lactoferrin-containing immunocomplexes drive the conversion of human macrophages from M2-into M1- like phenotype. Frontiers in Immunology, 2018, 9:37.
59 Rawat P., Kumar S., Sheokand N., Raje C.I., Raje M. The multifunctional glycolytic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a novel macrophage lactoferrin receptor. Biochemistry and Cell Biology, 2012, 90:329-338.
60 Takayama Y., Aoki R., Uchida R., Tajima A., Aoki Yoshida A. Role of CXC chemokine receptor type 4 as a lactoferrin receptor. Biochemistry and Cell Biology, 2017, 95:57-63.
61 Valenti P., Antonini G. Lactoferrin: an important host defence against microbial and viral attack. Cellular and Molecular Life Sciences, 2005, 62:2576-2587.
62 Shin K., Wakabayashi H., Yamauchi K., Yaeshima T., Iwatsuki K. Recombinant human intelectin binds bovine lactoferrin and its peptides. Biological and Pharmaceutical Bulletin, 2008, 31:16051608.
63 Suzuki Y.A., Lopez V., Lönnerdal B. Lactoferrin. Cellular and Molecular Life Sciences, 2005, 62:2560.
64 Kell D.B., Heyden E.L., Pretorius E. The Biology of Lactoferrin, an iron-binding protein that can help defend against viruses and bacteria. Frontiers in Immunology, 2020, 11:1221.
65 Milewska A., Zarebski M., Nowak P., Stozek K., Potempa J., Pyrc K. Human coronavirus NL63 utilizes heparan sulfate proteoglycans for attachment to target cells. Journal of Virology, 2014, 88:1322113230.
66 Azhar J., Mohammadabadi T., Babar M.E., Hussain T. Milk Lactoferrin: A Probable Immunological Agent Against SARS-CoV-2: A Review. Basrah Journal of Agricultural Sciences, 2020, 33(2):138-146.
67 Puddu P., Valenti P., Gessani S. Immunomodulatory effects of lactoferrin on antigen presenting cells. Biochimie, 2009, 91:11-18.
68 Britigan B.E., Lewis T.S., Waldschmidt M., McCormick M.L., Krieg A.M. Lactoferrin binds CpG-containing oligonucleotides and inhibits their immunostimulatory effects on human B cells. The Journal of Immunology, 2001, 167:2921-2928.
69 Legrand D., Elass E., Carpentier M., Mazurier J. Interactions of lactoferrin with cells involved in immune function. Biochemistry and Cell Biology, 2006, 84:282-290.
70 Queiroz V.A.O., Assis A.M.O., Júnior H.C.R. Protective effect of human lactoferrin in the gastrointestinal tract. Revista Paulista de Pediatria, 2013, 31:90-95.
71 Ishii K., Takamura N., Shinohara M. Longterm follow-up of chronic hepatitis C patients treated with oral lactoferrin for 12 months. Hepatology Research, 2003, 25:226-233.
72 Embleton N.D., Berrington J.E., Chris W.M., Cummings S.S. Lactoferrin: Antimicrobial activity and therapeutic potential. Seminars in Fetal & Neonatal Medicine, 2013, 18:143-149.
73 Mehta P., Mc Auley D.F., Brown M., Sanchez E., Tattersall R.S., Manson J.J. Across Specialty Collaboration, U. COVID-19: Consider cytokine storm syndromes and immunosuppression. The Lancet, 2020,395:1033-1034.
