The Role of l-J+ Macrophages in the Induction of Antigen B-Specific T-Suppressor Cells

Analysis of the two cell populations by cell surface antigens and a nonspecific esterase staining method that detects macrophages indicated that the B cells contained a 1 to 2% contamination of macrophages while the macrophage population was uncontaminated. Macrophages are not only required for antigen or anti-Id induction of T_s cells, but they also are required for the induction of T-suppressor factor induced T_s cells. The polyclonal anti-I-J^k antibody does bind weakly to some I-J^± AgB-specific T_s cells, suggesting that the I-J epitope on macrophages cross-reacts weakly with the I-J epitiope on T_s cells. Several investigators have suggested that the role of I-J might be to focus antigen or T suppressor factors to their appropriate target cells by interaction with I-J binding sites. Attempts to induce AgB-specific T_s cells in vitro using the F(Ab)2 fragment of anti-Id were unsuccessful, and others have similarly found that the F(Ab)2 fragments of anti-Id to be unable to induce suppressor cells.