Functional association of idiotypic and I-J determinants on the antigen receptor of suppressor T cells.

The serological characteristics of the antigen receptor on 4-hydroxy-3-nitrophenylacetyl (NP) specific suppressor T cell hybridomas were analyzed. Three T-cell hybrids could be lysed with anti-idiotype and complement. The reactivity pattern observed from a panel of anti-idiotypic reagents indicated that NPb determinants were detected on all three hybrid lines. NP conjugates with bovine serum albumin or caproic acid specifically inhibited the complement-mediated lysis of these cells by both anti-NPb idiotype and anti-I-J antisera. These hapten conjugates failed to block lysis by anti-Thy 1 or anti-H-2K antisera on the same target cell populations. The data indicate that both I-J and Igh variable region gene products are intimately involved in the recognition of antigen by suppressor T cells. Finally, the suppressor cell hybrids produce soluble factors that mediate antigen-specific suppression. The characteristics of the cells and their factors indicate that the hybrids correspond to the Tsi or first-order suppressor cells in the suppressor cell pathway.