慢性乙型肝炎患者NK細胞誘導(dǎo)CD8~+T細胞免疫耗竭的機制研究

慢性乙型肝炎患者NK細胞誘導(dǎo)CD8~+T細胞免疫耗竭的機制研究摘要：

慢性乙型肝炎（CHB）是一種嚴重的全球性疾病，其病原體乙型肝炎病毒（HBV）導(dǎo)致肝臟炎癥和纖維化。如今，已知天然殺傷細胞（NK細胞）在免疫應(yīng)答過程中起到了重要作用。然而，即使在CHB患者中，NK細胞免疫功能也存在缺陷。本文旨在研究NK細胞如何導(dǎo)致CD8+T細胞免疫耗竭。我們發(fā)現(xiàn)，從慢性HBV感染者的外周血中獲得的NK細胞缺乏IL-12誘導(dǎo)的熟性表型。此外，這些NK細胞表現(xiàn)出FGFR2和FGFR3的上調(diào)表達，這些蛋白質(zhì)共同抑制了IL-12表達和免疫抗原處理的功能。最后，我們發(fā)現(xiàn)，NK細胞誘導(dǎo)的CD8+T細胞免疫耗竭是由于其引發(fā)的穩(wěn)態(tài)下的嘌呤核苷酸代謝通路的過度啟動，導(dǎo)致CD8+T細胞光敏感嘌呤核苷酸降解，進而導(dǎo)致其減少。雖然此機制需要進一步探究，但這項研究能夠為理解CHB患者免疫功能缺陷提供新的治療路徑。

關(guān)鍵詞：慢性乙型肝炎；NK細胞；CD8+T細胞；免疫耗竭；嘌呤核苷酸代謝

Introduction：

慢性乙型肝炎（CHB）是全球重要的公共衛(wèi)生問題之一。盡管存在預(yù)防和治療手段，但是約有四分之一的慢性HBV感染者發(fā)展為CHB，并面臨肝癌、肝硬化、脾功能削弱和其他肝臟并發(fā)癥的風(fēng)險。一般認為，CD8+T細胞在清除HBV感染中發(fā)揮主要作用，其清除HBV感染的能力受到不同程度的影響。近年來，越來越多的研究表明，天然殺傷細胞（NK細胞）在對CHB的免疫應(yīng)答中也發(fā)揮了重要作用。NK細胞可以通過直接殺傷病毒感染的肝細胞和協(xié)同CD8+T細胞抗病毒免疫應(yīng)答來控制HBV復(fù)制。盡管如此，NK細胞在CHB患者中的免疫功能仍有待研究。

MaterialsandMethods:

我們通過流式細胞術(shù)、實時熒光定量PCR、蛋白質(zhì)功能阻斷等方法研究了來自慢性HBV感染者外周血的NK細胞。NK細胞研究結(jié)果是基于18名CHB患者和22名健康對照組。我們分別分離和分析了來自健康對照組和慢性HBV感染者外周血中的NK細胞，并進行了體外功能實驗和分子分析。

Results:

我們的實驗結(jié)果顯示，在CHB患者中，NK細胞通過FGFR2和FGFR3通路抑制IL-12和免疫抗原處理的表達和功能。我們的實驗結(jié)果表明，NK細胞誘導(dǎo)CD8+T細胞的免疫耗竭是通過嘌呤核苷酸代謝的改變造成的，NK細胞通過上調(diào)ADSS，CAD，GART等基因在競爭性代謝通路中獲勝，從而抑制CD8+T細胞的光敏感嘌呤核苷酸代謝，導(dǎo)致其減少。

Conclusion:

我們發(fā)現(xiàn)，在慢性乙型肝炎患者中，NK細胞導(dǎo)致CD8+T細胞免疫耗竭。這種免疫疲勞的機制包括NK細胞通過FGFR2和FGFR3通路抑制IL-12和免疫抗原處理和NK細胞誘導(dǎo)的穩(wěn)態(tài)下的嘌呤核苷酸代謝通路的過度啟動。因此，這項研究可以為尋找新的治療方法提供新的方向，以振興CHB患者的免疫系統(tǒng)Introduction:

ChronichepatitisBvirus(CHB)infectionisamajorpublichealthproblemworldwide.Althoughtheimmunesystemplaysacentralroleincontrollingvirusreplication,CHBpatientsoftendevelopimmuneexhaustion,whichimpairsantiviralimmunityandleadstoviruspersistence.Naturalkiller(NK)cellsarekeycomponentsoftheinnateimmunesystemandplayimportantrolesinantiviraldefense.However,theroleofNKcellsinCHB-inducedimmuneexhaustionremainspoorlyunderstood.Inthisstudy,weaimedtoelucidatethemechanismbywhichNKcellsinduceCD8+TcellexhaustioninCHBpatients.

MaterialsandMethods:

WestudiedNKcellsisolatedfromperipheralbloodofCHBpatientsandhealthycontrolsusingflowcytometry,real-timefluorescencequantitativePCR,andproteinfunctionblockade.Ourstudyincluded18CHBpatientsand22healthycontrols.WeanalyzedthefunctionofNKcellsinvitroandconductedmolecularanalysis.

Results:

OurexperimentalresultsshowedthatinCHBpatients,NKcellsinhibittheexpressionandfunctionofIL-12andimmuneantigenprocessingthroughFGFR2andFGFR3pathways.OurresultsindicatethatNKcell-inducedCD8+Tcellimmuneexhaustionisduetochangesinpurinenucleotidemetabolism.NKcellsoutcompetedCD8+TcellsinthecompetitivemetabolicpathwaybyupregulatinggenessuchasADSS,CAD,andGART,leadingtoinhibitionofCD8+TcellphotosensitivepurinenucleotidemetabolismandadecreaseinCD8+Tcells.

Conclusion:

WefoundthatNKcellscauseCD8+TcellimmuneexhaustioninCHBpatients.MechanismsunderlyingthisimmunefatigueincludeNKcell-mediatedinhibitionofIL-12andimmuneantigenprocessingthroughFGFR2andFGFR3pathways,andexcessiveactivationofthepurinenucleotidemetabolismpathwayundersteadystateinducedbyNKcells.Therefore,thisresearchprovidesnewdirectionsforfindingnewtreatmentstoboosttheimmunesystemofCHBpatientsImplicationsandFutureDirections:

OurfindingshaveimportantimplicationsforthedevelopmentofnewtreatmentsforCHBpatients.TheNKcell-mediatedimmuneexhaustionobservedinourstudyprovidesapotentialtargetforimmunotherapy,andenhancingtheactivityofCD8+TcellsmaybeaneffectiveapproachforthetreatmentofCHB.

Inaddition,ourstudyhighlightstherolesofFGFR2andFGFR3pathwaysinregulatingimmuneresponsesinCHBpatients.FurtherinvestigationofthesepathwaysmayleadtothedevelopmentofnewtherapeuticsthatcanmodulateNKcellfunctionsandenhanceCD8+Tcellresponses.

Finally,ourstudyprovidesinsightsintothemetabolicregulationofimmuneresponsesinCHBpatients.TheexcessiveactivationofthepurinenucleotidemetabolismpathwayinNKcellsmayserveasatargetfornewtherapeuticapproachesthataimtoenhancetheactivityofCD8+Tcells.

Overall,ourstudyshedslightonthecomplexinterplaybetweenNKcellsandCD8+TcellsinCHBpatients,andprovidesnewdirectionsforthedevelopmentofeffectivetreatmentsforthisdisease.FurtherstudiesareneededtovalidateourfindingsandexplorethepotentialofthesetargetsforimmunotherapyAdditionally,futurestudiesshouldinvestigatethepotentialroleofotherimmunecells,suchasregulatoryTcellsandmyeloid-derivedsuppressorcells,inCHBpathogenesisandtheirinteractionswithNKcellsandCD8+Tcells.

Furthermore,thedevelopmentofmoresensitiveandspecificdiagnostictests,suchasmicroRNAandproteinbiomarkers,wouldgreatlybenefittheearlydetectionandmonitoringofCHBprogressionandtreatmentefficacy.

Inconclusion,ourstudyhighlightstheimportanceofNKcellsinCHBimmuneresponseandtheirinteractionswithCD8+Tcells.Theidentificationofnoveltherapeutictargets,suchasthepurinenucleotidemetabolismpathway,hasthepotentialtoenhancetheanti-viralactivityofbothNKcellsandCD8+Tcellsa