MHC Ⅰ类分子递呈修饰后抗原的结构与免疫学研究的开题报告

MHCⅠ类分子递呈修饰后抗原的结构与免疫学研究的开题报告摘要：MHCⅠ类分子是通过递呈抗原来激活CD8+T细胞并介导细胞免疫反应的关键途径。抗原递呈分子部分以β2微球蛋白和α链组成，不同的共表达抗原可在其N末端的多态性域中被特异性结合并递呈给T细胞。然而，MHCⅠ类分子表面的修饰也被确认可影响其功能。其中，磷酸化修饰被发现可调控抗原递呈及T细胞发育过程。因此，本研究拟通过对MHCⅠ类分子进行磷酸化修饰来研究其在抗原递呈中的作用，并分析其对T细胞免疫应答的影响。关键词：MHCⅠ类分子；抗原递呈；修饰；磷酸化；T细胞IntroductionMajorhistocompatibilitycomplex(MHC)ImoleculesareessentialfortheactivationofCD8+T-cell-mediatedcell-mediatedimmuneresponsesbypresentingantigenicpeptidesderivedfromintracellularproteins(1).TheMHCImoleculeiscomposedofβ2-microglobulin(β2m)andanαchain,whichconsistsofthreeextracellulardomains:α1,α2,andα3.Polymorphicregionsontheα-chainenablethespecificbindingandpresentationofarangeofpeptidestoCD8+Tcells(1,2).AlthoughthefunctionalrolesofMHCImoleculesinantigenpresentationarewellestablished,recentstudieshavealsoshownthatpost-translationalmodification(PTM)ofMHCImoleculescanaffecttheirantigenpresentingcapabilityandT-cellimmunogenicity(3,4).PTMssuchasphosphorylationhavebeenidentifiedaskeyregulatorsofMHCIantigenpresentationandT-celldevelopment(4-6).AnalysisofMHCImoleculesfromT-celldepletedmicerevealedthatasignificantportionofMHCImoleculesarephosphorylatedattyrosineresidues(6).FunctionalstudieshaveshownthatthisphosphorylationcanenhanceantigenpresentationbypromotingMHCIassociationwithchaperones,stabilizingpeptidebinding,andenhancingT-cellactivation(5,7,8).Additionally,phosphorylationofMHCImoleculeshasbeenshowntoregulateT-celldevelopment,withlossofphosphorylationleadingtodecreasedpositiveselectionofthymocytes(4).However,thepreciseroleofMHCIphosphorylationinantigenpresentationandT-cellimmunogenicityremainspoorlyunderstood.Therefore,thisstudyproposestoinvestigatetheeffectsofMHCIphosphorylationonantigenpresentationandT-cellimmuneresponsesthroughtheuseofinvitrotechniques.Specifically,MHCImoleculeswillbepurifiedfrommurinetissuesandphosphorylatedinvitro.ThesemodifiedMHCImoleculeswillthenbeassessedfortheirabilitytopresentantigenicpeptidesandstimulateT-cellactivationusingavarietyofimmunecellassays.ObjectivesTheobjectiveofthisstudyistoinvestigatetheroleofMHCIphosphorylationinantigenpresentationandT-cellimmuneresponses.Specifically,thisstudyaimsto:1.PurifyMHCImoleculesfrommurinetissues.2.PhosphorylateMHCImoleculesusinginvitrotechniques.3.DeterminetheantigenpresentingcapabilityofphosphorylatedMHCImolecules.4.AnalyzetheeffectsofMHCIphosphorylationonT-cellactivationandimmuneresponses.Methods1.MHCIpurification:MHCImoleculeswillbepurifiedfrommurinetissuesusingaffinitychromatographywithanti-MHCIantibodies.2.MHCIphosphorylation:PurifiedMHCImoleculeswillbephosphorylatedinvitrousingrecombinanttyrosinekinases.3.Antigenpresentationassays:PhosphorylatedMHCImoleculeswillbeassessedfortheirabilitytopresentantigenicpeptidesusingavarietyofimmunecellassays,includingT-cellproliferation,cytokineproduction,andcytotoxicityassays.4.T-cellactivationassays:TheeffectsofMHCIphosphorylationonT-cellactivationandimmuneresponseswillbeanalyzedusingflowcytometryandELISAassays.ExpectedOutcomesThisstudyisexpectedtoprovidenewinsightsintotheroleofMHCIphosphorylationinantigenpresentationandT-cellimmuneresponses.Specifically,itisanticipatedthatphosphorylationofMHCImoleculeswillenhancetheirantigenpresentingcapabilityandpromoteT-cellactivation,leadingtoenhancedimmuneresponses.Thisstudyisalsoexpectedtorevealtheunderlyingmolecularmechanismsresponsiblefortheseeffects,whichmayhaveimportantimplicationsforthedevelopmentofnewimmunotherapiesthattargetMHCImolecules.ConclusionMHCImoleculesarecentraltotheactivationofCD8+T-cell-mediatedcell-mediatedimmuneresponses.Post-translationalmodificationssuchasphosphorylationhavebeenshowntoregulateMHCIantigenpresentationandT-celldevelopment.Therefor