Previous studies from this laboratory have shown that staphylococcal enterotoxin B (SEB) has the capacity to nonspecifically induce multiple T suppressor cell populations which are capable of regulating both primary and secondary in vitro antibody responses. Additional studies have revealed that the suppressive activity of these cells is mediated, at least in part, by an I-J-restricted suppressor-inducer factor. Efforts to characterize the specificity of this inducer molecule have demonstrated the presence of multiple antigen-specific suppressor factors within SEB-stimulated supernatants. Antigen-binding molecules present within these SEB-induced factor preparations were isolated and concentrated over antigen-coupled columns. The results have demonstrated that eluates from trinitrophenyl-ovalbumin and trinitrophenyl-keyhole limpet hemocyanin-coupled columns significantly suppress both primary and secondary anti-TNP plaque-forming colony responses, whereas the filtrates from these columns demonstrated little to no inhibitory activity. The filtrates, but not eluates, from these columns exhibited significant suppressive activity for anti-poly(L-Phe,L-Glu)-poly-DL-Ala-poly-L-Lys, anti-azobenzenearsonate, and anti-sheep red blood cell antibody responses. Additional studies using eluates and filtrates from a variety of antigen-coated columns have demonstrated that suppressor factors of multiple antigenic specificities are present within SEB-induced supernatants. These studies suggest that SEB polyclonally activates antigen-specific suppressor cells which produce suppressor factors which specifically regulate the antibody response.