MHC restriction of male-antigen-specific T helper cells collaborating in antibody responses.

By priming female C57BL/6 mice with syngeneic male spleen cells and enriching inguinal and paraaortic lymph node cells in long-term culture (LTC) by repeated restimulations, H-Y-specific T helper cells can be produced. In response to male spleen cells carrying I-Ab antigens these cells activate "antigen-expressing" B cells to secrete polyclonal antibody. Before the end of the second week in LTC it was impossible to detect any helper activity. Induction of plaque-forming cells (PFC) also requires simultaneous recognition of antigen and I-A-encoded determinants in the "stimulator-responder" spleen-cell population. The testing of spleen cells from H-2 recombinant strains as "stimulator-responders" to anti-H-Y helper T cells of C57BL/6 origin also revealed that other genes, telomeric to I-A, control the magnitude of both specific T-cell proliferation and helper-dependent B-cell activation.