Comparison of neonatally and adoptively induced transplantation tolerance in mice.

Transplantation tolerance induced by the semiallogeneic cells in newborn mice or by the adoptive transfer of syngeneic spleen cells from neonatally tolerant donors in adult mice was studied in the strain combination with the H-2D region disparity (B10.A recipients--B10.A(2R) donors). Tolerance could be transfered adoptively already from 3-week-old mice that had been rendered tolerant at birth and the ability for the transfer of tolerance persisted for long periods even when neonatally tolerant animals were not skin grafted. Both neonatally and adoptively induced tolerance could not be abolished by the adoptive transfer of 100 x 10(6) immunocompetent cells from normal syngeneic donors. It was observed in the in vitro experiments that cells from tolerant mice in the two types of tolerance reacted to the tolerated antigens in the mixed lymphocyte culture, did not react to the tolerated antigens in the microcytotoxicity test (only some mice with adoptively induced tolerance showed a certain degree of reactivity), but cells from both types of tolerant mice inhibited the in vitro sensitization of cells from normal syngeneic animals. This suppression was stronger with cells from neonatally tolerant mice.