Differential effects of alloimmunization on T cells mediating graft-vs-host splenomegaly or the allogeneic effect in F1 mice.

Spleen cells from normal BALB/c mice or mice immunized 10 or 30 days previously with C57BL/6 spleen cells were tested for a) their capacity to produce graft-vs-host (GVH) reactions in newborn F1 mice and b) their capacity to produce an allogeneic effect in adult F1 mice immunized with Type III pneumococcal polysaccharide. GVH reactivity of alloimmune spleen cells obtained 10 or 30 days after immunization was significantly increased as compared to the reactivity of normal spleen cells in that a) at comparable cell doses, higher spleen indices were obtained with alloimmune cells than normal cells, and b) alloimmune cells produced severe runting at lower cell doses than normal cells. By comparison, the capacity of alloimmune spleen cells to produce an allogeneic effect was reduced 50% on a per cell basis as compared to normal spleen cells at both 10 and 30 days after immunization. These results give further evidence that T cells producing the allogeneic effect are distinct from the T cell populations which interact to produce GVH splenomegaly.