Role of I-J-subregion gene products in the regulation of macrophage-T-lymphocyte interaction

Pretreatment of splenic macrophages with anti-Ia serum specific for the various known I subregions and complement deleted the macrophages required for an in vitro antibody response to burro erythrocytes. Antibodies directed at the gene products of the I-J subregion, however, were unique in that they did not require the presence of complement. When macrophages and macrophage depleted cells were obtained from strains B10.A(3R) and B10.A(5R) differing only at the I-J subregion, they could not be mixed in culture for an effective response. Differences at other I subregions using alternative strain combinations resulted in an enhanced response. These results suggest that the I-J subregion has a critical role in macrophage-T cell interaction.