Generation in vivo of non-T suppressor cells with the use of anti-allotype antibody.

Anti-Igh-1b antiserum induced allotype-specific suppression of adult mouse spleen cells in an adoptive transfer system. Suppression of Igh-1b anti-sheep red blood cell plaque-forming cells was measured as late as 4 wk after the injection of allotype heterozygous (Igha/b) spleen cells, antiserum, and sheep red blood cells. Suppression was maintained on retransfer of the allotype-suppressed spleen cells to further irradiated recipients in the absence of additional exogenous anti-allotype antibody. Mixing experiments were performed to test the putative inhibitory effects of allotype-suppressed spleen cells from the first adoptive transfer (stage I) on the antibody response of normal spleen cells in a second adoptive transfer (stage II). No suppression was observed by using unfractionated stage I spleen cells. In contrast, when these allotype-suppressed spleen cells were depleted of T cells, they strongly inhibited the antibody production of admixed normal spleen cells in stage II. This inhibitory activity of antibody-induced stage I spleen cells was directed primarily toward the target allotype, but some suppression of the Igh-1a plaque-forming cell response and total IgG production also occurred. Although removal of adherent cells did not affect the inhibitory activity of allotype-suppressed spleen cells from stage I, removal of Ig+ cells completely abrogated the inhibitory activity. These results suggest that antibody-induced regulatory B cells may play a role in maintaining long term allotype suppression.