Collaboration between histoincompatible T and B lymphocytes: preferential induction in vivo of antibodies to antigens borne by foreign T cells

Abstract

We have compared, in vivo, with nude mice and, in vitro, with cultures of T depleted spleen cells, several components of the humoral response resulting from the helper effect of allo- or xenogeneic T cells on mouse B lymphocytes; the response directed to the histocompatibility antigens (or other surface antigens) borne by foreign T lymphocytes, the effect on the response to an additional unrelated antigen, namely sheep red blood cells, and finally a possible nonspecific polyclonal activation. In vivo, injection of allo- or xenogeneic T lymphocytes into nude mice (with or without SRBC) induced a strong anti-T cell response, manifested by the presence of high titered IgG alloantibodies, without significant enhancement of the response to SRBC. In vitro, addition of xenogeneic T lymphocytes to cultures of T-depleted spleen cells did enhance an anti-T cell and an anti-SRBC response. The preferential induction of an anti-T cell response, observed in vivo, implies a peculiar form of T-B cell collaboration where the B lymphocytes binding to the foreign and activated T cells are selectively activated, suggesting that there is no absolute restriction for specific T-B cell collaboration across the histocompatibility barrier.