Cooperation of murine F T and parental B lymphocytes in rejection of a xenogeneic tumour: adaptive differentiation of B lymphocytes?

The primary humoral immune response to rat Yoshida ascites sarcoma (YAS) grown in mice was used to study thymus-dependent (T) and bone marrow-derived (B) lymphocyte cooperation. It was shown that B6D2F1 T lymphocytes that do not cooperate with parental B lymphocytes enabled parental B lymphocytes from B6 leads to B6D2F1 radiation chimaeras to reject the tumour. However, when the bone marrow cells from B6 leads to B6D2F1 chimaeras were used to reconstitute parental B6 mice, these B6 leads to B6D2F1 leads to B6 mice lost their tolerance to D2 transplantation antigens, and their B lymphocytes were not able to cooperate with B6D2F1 T lymphocytes. In our search for the reasons for the failure of F1 T cells to be effective in parental and P leads to F1 leads to P TIR mice, rejection of F1 T cells was excluded because : (i) immune reactivity in TIR mice was found to be either absent or minimal; (ii) parental TIR mice did not produce any detectable cytotoxic antibodies after an intravenous injection of F1 splenic T cells; and (iii) YAS rejection was not induced at very high doses of F1 T cells. However, in a cell transfer system we were able to demonstrate that injection of spleen cells from parental TIR mice could thwart the successful cooperation of transferred F1 T cells with host B cells. Collectively, these data suggest that the changes of the collaborative potential of parental B cells as achieved in the F1 environment could be ascribed to 'adaptive' differentiation of B lymphocytes. It appears that the differentiation process that has rendered nonsyngeneic chimaeric cells able to cooperate was independent of the exogenous antigen.