Ability of an anti-T-cell serum to dissociate two features of cellular hypersensitivity in the guinea-pig.

Guinea-pigs immunized with reactive 2,4-dinitrophenyl (DNP) sensitizer in Freund's complete adjuvant develop delayed-onset reactivities to the reactive DNP sensitizer and to DNP protein conjugates as well as to PPD. We have studied the role of various lymph node lymphocyte populations from these animals in producing the lymphokine macrophage agglutination factor (MAggF) and effecting antigen induced blast transformation. The production of MAggF, when elicited by reactive sensitizer or PPD, was readily inhibited by low doses of a particular cytotoxic rabbit and anti-T (thymus-dependent)-lymphocyte serum and complement, while the production of MAggF when elicited by DNP protein conjugate was inhibited only by higher doses of anti-T-cell serum. These results in vitro paralleled earlier observations in vivo. In contrast, PPD induced blast transformation was only inhibited by high doses of anti-T-cell serum and not by low doses. Chromatography of sensitized lymph node cells over anti-Ig-containing columns (to remove B cells) affected neither MAggF production nor blast transformation. Our data suggest that these in vitro responses are mediated by two different subpopulations of T cells.