Cell-mediated lympholytic responses against autologous cells modified with haptenic sulfhydryl reagents. I. Effector cells can recognize two distinct classes of hapten-reactive self sites on cell surface proteins.

Mouse spleen cells were modified with a sulfhydryl-reactive reagent, N-iodoacetyl-N'-(5-sulfonic-1-naphthyl) ethylene diamine (I-AED) and used as stimulator cells in primary in vitro cultures with unmodified spleen cells of the same strain. CTL could be readily demonstrated when tested on hapten-modified syngeneic target cells. These CML responses were hapten specific and H-2 restricted. In the H-2b strain, effector cell populations were identified that recognized AED in association with K-end and D-end coded self MHC products. Functional modification of the target cells by I-AED can be effectively blocked by prereacting the cells with other SH-reagents, which is consistent with CTL recognition of the hapten on cysteine residues. Since these premodifications of the cell surface do not block the functional modification by trinitrobenzene sulfonate (TNBS), the sulfhydryl-reactive compounds and TNBS modify distinct classes of cell surface groups as determined by CTL function. The results of antibody inhibition experiments are also consistent with this interpretation. Using fluorescent labeled anti-hapten antibodies, FACS II analysis showed that there are approximately 20-fold fewer AED than TNP groups on the approximately 20-fold fewer AED than TNP groups on the cell surface when equivalent concentrations of I-AED and TNBS are compared. The possibility is discussed that these sulfhydryl-reactive compounds can be used together with the H-2Kb mutants for the localization of H-2 coded self determinants recognized in association with foreign antigens.