Structural characterization of developmentally expressed antigenic markers on chicken erythrocytes using monoclonal antibodies☆

[摘要] Monoclonalantibodiesselectedforembryonicandadulterythrocytespecificityhavebeenusedtocharacterizedevelopmentallyexpressedmarkersonthesurfacesofmaturecirculatingerythrocytesofyoungandadultchickens.Thedatapresenteddemonstratethattheantigenicchangeswhichoccurontheavianerythrocytemembranewithorganismicmaturationcanbeaccountedfor,atleastinpart,bychangesintheexpressionofstructurallydifferent,butpossiblyrelatedpolypeptides.Monoclonalantibodiesselectedforspecificreactivitywiththeerythrocytesofnewlyhatchedchicksrecognizeaglycoproteinof48,000daltonsapparentmolecularweight.Ontwo-dimensionalisoelectricfocusinggels,thisantigen,whichappearsidenticalinallstrainsstudied,displaysmicroheterogeneity;consistingofeighttoninecloselyspacedspotswithanisoelectricmidpointofapproximately5.5.Thisantigenisnotexpressedonthecirculatingerythrocytesofmaturebirds;however,anantigenwithsimilar,butperhapsnotcompletelyidenticalstructure,canbedetectedwithintheadultbonemarrow.Themonoclonalantibodieswhichshowpreferentialbindingtothecirculatingerythrocytesofadultbirdsalsoimmuneprecipitateanantigenof48,000daltonsapparentmolecularweight,butthisantigenhasamorebasicisoelectricpoint.Theadultantigenispolymorphic.Slightlydifferentpatternswereobtainedontwo-dimensionalgelswitherythrocytesfrominbredbirdshavingdifferentmajorhistocompatibilitygenotypes.IthasamajorcomponentnearpH7.0andadditionalfocusingspotsusuallyoccurringataslightlylowermolecularweightnearpH6.8or6.6dependinguponstrain.CompetitiveradiobindingassayswithB-system-specificalloantiserssuggestthattheseantigensmayinfactbeantigensofthepolymorphicBGlocusofthechickenmajorhistocompatibilitycomplex.One-dimensionalpeptidemappingoftheimmuneprecipitatedembryonicandadulterythrocytepolypeptidesdemonstratethattheantigensareborneondistinctbutpossiblyrelatedpolypeptides.Bothcommonanduniquepeptidefragmentsarefoundinthedigestionproducts.Selectivesolubilizationofthechickenerythrocytemembranesuggeststhattheantigensareintegralmembraneproteinsextractablewithnonionicdetergentbutnotwithreagentswhichremoveperipheralproteins.

[学科分类] 生物科学（综合）