The Morphologic Responses of the Lymphoid System to Homografts. II. The Effects of Antimetabolites

Abstract

Abstract The effects of 6-mercaptopurine and thioguanine on the morphologic responses of lymph nodes and spleen were studied in the rabbit. The main effect of these drugs was to inhibit the proliferation of hemocytoblasts, cells considered to be immunologically competent. Homograft rejection did not occur as long as these cells were suppressed. Rabbits which rejected their grafts in spite of continued 6-mercaptopurine treatment developed large numbers of hemocytoblasts in their lymphoid apparatus. These cells were thought to be drug resistant and analogous to resistant leukemic cells.