Role of genes in murine major histocompatibility complex (MHC) in the ontogeny of B cells with restricted capacity for cooperation with adherent cells in the production of antibody to thymus-dependent (TD) and thymus-independent type 2 (TI-II) antigens.

We have examined the MHC restriction that exists for cooperation between B lymphocytes and antigen-pulsed accessory cells for antibody responses in tissue culture, using B cells prepared from spleen cell suspensions of progeny born to (B10 x B10.BR)F1 female mice mated with B10 males. At early times post-birth (3 to 6 wk) progeny animals types as H2b contained a population of splenic B cells restricted to MHC antigens expressed on B10.BR macrophages; in contrast, B cells from H2b animals born to the incross (B10 x B10) were as expected, restricted to cooperate only with B10 macrophages. This unusual restriction pattern waned with age such that by 20 wk of age considerably fewer of the B10 progeny born in the backcross mating exhibited this behavior. We interpret these data as evidence that the early B cell repertoire is to some degree 'driven' by exposure to those MHC antigens (in the maternal placental circulation) encountered in utero. Post-birth, continued renewal of the mature B cell pool occurs concomitant with a diversification (and selection) of the B cell repertoire as a result of experience with antigens lacking this maternally imparted genetic information.