Target Lymphoid Cell Population of Carcinogen Induced Immunodepression in Mice

Abstract

EXPOSURE to a number of carcinogenic agents results in a depression of immune status1. In detailed studies of chemical carcinogenesis in mice, Stjernsward2,3 has shown that methylcholanthrene, benzpyrene and dimethylbenzanthracene (DMBA), all potent carcinogens, depress the immune response to sheep red cells (SRBC) for a long period following a single small carcinogenic dose of the agent. Although it seemed likely from these studies that the carcinogens act on the cells involved in the immune response, no direct evidence was presented. Recent work4–10 in a number of independent laboratories clearly demonstrates that a variety of cell-mediated immune responses, including those to SRBC, involve the interaction of two distinct classes of lymphocyte—the thymusderived cell responsible for reacting with antigen and the bone-marrow derived cell that is the precursor of the antibody-forming cell. The present study was designed to show whether carcinogen-induced immunodepression was a phenomenon linked to cells involved in the immune response and, if so, which of the interacting classes of cell was the target for this effect.