FURTHER ANALYSIS OF ELIMINATION OF RUNT DISEASE AND INDUCTION OF TOLERANCE BY X-IRRADIATED SPLEEN CELLS1

Abstract

In these studies a quantitative estimate was made of the decrease in proliferative capacity and immunologic activity of spleen cells exposed to 400 r of total body X-irradiation. The decreased proliferative capacity of irradiated CBA spleen cells was inferred from a decreased ability to induce homograft tolerance in newborn C3H mice as compared to the ability of various doses of non-irradiated CBA spleen cells to induce homograft tolerance. The decreased immunologic activity of CBA spleen cells was estimated from a decreased capacity to induce a graft-versus-host reaction in newborn C57BL/6 mice as compared to the capacity of standard doses of non-irradiated CBA cells to elicit a graft-versus-host reaction. The results indicate that 400 r of total body X-irradiation reduces the proliferative capacity of CBA spleen cells by about 95-96% and the immunologic activity by about 98-99%.