Antibody production by transferred lymphoid cells: inhibition by competition of antigens.

A/Jax and C57BL mice were immunized with either human red blood cells or with both human cells and (A/Jax×C57BL)F hybrid spleen cells, and sensitized spleen cells were transferred to isogeneic or hybrid hosts. Anti-human haemagglutinin titres were lower in hosts receiving C57BL rather than A/Jax cells, were lower in hybrid than isogeneic hosts, and were lower in animals receiving doubly- than in those receiving singly-sensitized cells. The results can be best interpreted on the basis of competition of antigens, rather than by postulating allergic death of sensitized lymphoid cells exposed to an overwhelming dose of antigen. Competition of antigen was found to occur in A/Jax and C57BL mice actively immunized with both human red cells and hybrid spleen cells, when antibody titres were compared with those of singly-immunized controls. Anti-human haemagglutinin titres in actively immunized hybrid mice were intermediate between those of the parental strains, suggesting that differences in titres between the parental strains were due to physiological differences in the antibody-forming system, rather than to the more poorly reacting strain sharing antigenic determinants with and therefore being partially tolerant to human red cells.