Immunosuppression of normal lymphoid cells by serum from mice undergoing chronic graft-vs-host disease.

Spleen cells from F1 mice undergoing chronic graft-vs-host (GVH) reaction, induced by injection of parental cells, were shown to be immunosuppressed since their in vitro responses to the mitogens concanavalin A (Con A) and bacterial lipopolysaccharide (LPS) were substantially lower than control animals. Serum, from mice undergoing GVH, when cultured in vitro with normal spleen cells was immunosuppressive. The proliferation response to Con A and allogeneic cells of normal syngeneic, allogeneic, and parental spleen cells was 90% suppressed when serum from mice undergoing chronic GVH was added in comparison to the addition of serum from untreated F1 mice. Similarly, the in vitro antibody response to a T-dependent antigen was impaired; however, the antibody response to a T-independent antigen was not impaired. These results indicate that T cell functions are more sensitive than are B cell functions to immunosuppressive factors in the serum of mice undergoing GVH.