Allogeneic H-2 dose not cross-react, at the helper T-cell level, with Hapten-modified Self

Helper T cells raised in CBA mice and enriched in vitro with specificity for trinitrophenylmodified syngeneic spleen cells can activate hapten-modified B cells bearing Ik. These helper cells fail to activate B cells expressing any of six independent I-region haplotypes, indicating lack of cross-reactivity between hapten-self and allogeneic I-region products. Furthermore, hapten-derivatized allogeneic B cells are also not activated, demonstrating that the elements restricting T-cell function are poorly, if at all, cross-reactive.