The role of H-2-linked genes in helper T-cell function: I. In vitro expression in B cells of immune response genes controlling helper T-cell activity*

Abstract

The ability of murine helper T cells primed to the antigen, sheep erythrocytes (SRBC) to cross-react with burro erythrocytes (BRBC) in the in vitro antitrinitrophenol (TNP) response to TNP-RBC was shown to be under genetic control. Although non-H-2 genes were shown to influence the absolute level of helper activity assayed aider SRBC priming, the extent of cross-reaction of SRBC-primed helpers with BRBC was shown to be controlled by an H-2-1inked Ir gene(s). H-2 haplotypes were identified which determined high, intermediate, or low response to the cross-reacting determinants and the gene(s) controlling the cross-reaction tentatively mapped to the K through I-E end of the H-2 complex. Helpers primed in F1 mice of high × intermediate or high × low respender parents were tested for cross-reaction using B cells and macrophages (Mπ) of parental haplotypes. In each case the extent of cross-reaction was predicted by the H-2 haplotype of the B cells and Mπ, establishing the expression of the Ir gene(s) in B cells and/or Mπ at least, but not ruling out its expression in T cells as well. The low cross-reaction seen when T cells from F1 mice of high × low responder parents were tested on low responder B cells and Mq5 was not increased by the presence of high responder Mπ indicating the Ir gene(s) is expressed in the B cell at least although it may be expressed in Mπ as well. These and our previously reported experiments are consistent with the hypothesis that helper T cells recognize antigen bound to the surface of B cells and Mπ in association with the product(s) ofIr gene(s) expressed on the B cell and Mπ. © American Society for Clinical Pathology.