ATHYMIC (NUDE) MICE FAIL TO DELETE FUNCTIONAL SELF-REACTIVE HELPER T-CELLS

We have examined the thymic requirement for the antibody response to a foreign antigen coupled to self erythrocytes. We find that self eryth rocytes mediate thymus-independent, carrier specific help for the anti body response to the pneumococcal cell wall polysaccharide antigen, Pn C. Thus, athymic nude mice gave a high primary antibody plaque-forming cell (PFC) response to PnC-mouse RBC but a low response to PnC couple d to sheep or burro RBC. The meager response to PnC coupled to foreign RBCs could not be attributed to antigenic competition since the respo nse to the carrier (burro RBC) was < 100 PFC per spleen. Reconstitutio n of nude mice with splenic T cells from euthymic mice enhanced rather than suppressed the antibody response to PnC-mouse RBC. The results d ocument that in the absence of thymic deletion, functional self-reacti ve helper cells persist in the nude mouse.