BackgroundInformation | CD4isa55kDaglycoproteinwithfourimmunoglobulin-likeexternaldomains,atransmembranedomainandahighlyconservedintracellulardomain(Leong,1999).CD4actsasacoreceptorinMHCclassII-restrictedantigen-inducedT-cellactivation.Further,CD4hasaroleintheregulationofT-Blymphocyteadhesionintheabsenceofantigenrecognition,andinthymicdifferentiation(Piatier-Tonneau,2002).CD4isexpressedonthymocytesubsets,itmarkshelper/inducerTcells,anditisexpressedin55-65%ofmatureperipheralTcells.SubpopulationsofsuppressororcytotoxicTcellscanbeidentifiedamongCD4-positiveTcells.CD4isalsoexpressedonmonocytes/macrophages,Langerhanscellsandotherdendriticcells.CD4isnotexpressedonBcells.Anti-CD4,MT310,wasincludedintheSecondInternationalWorkshopandConferenceonHumanLeucocyteDifferentiationAntigens,andstudiesbyanumberoflaboratoriesconfirmeditsreactivitywiththeCD4antigen(Miedema,1986). |