active clonotypic B cell response directed toanimmunogenic region ofthehuman#2-adrenergic receptor

SUMMARY Ithasbeenreported thatautoantibodies against the#2-adrenergic receptors areinvolved inthe pathology ofallergic disorders andofChagas' disease. Therefore, theimmuneresponse against a peptide (H26Q) correspo dingtotheputative second extracellular loop ofthehumanf2-adrenergic receptor, whichcouldbe target forautoantibody attack, wasanalysed inviewofitspossible immunogenicity. Thefree pptide induced aTcell-mediated humoral response inthecontext ofthree different murine MHC haplotypes. TheTcell epitope wasfoundtobelocalized intheN-terminal region ofthepeptide. Highly specific T helper cells werecapable ofstimulating B cells withthe potential togenerate alarge antibody repertoire reactive withtheloop peptide. MoAbswerescreened toanalyse this Bcell response forantibodies potentially interfering withreceptor function anda MoAbwasfound thatimpaired ligand binding tothereceptor.