[Surface markers and humoral factors in spontaneous murine leukemia]

This paper presents a model of spontaneous BALB/c lymphoma (LB) useful for the study of the relationship between the tumor and the immune system. Characterization of this tumor was done by FACS and it was determined that the tumor cells are T lymphocytes which express both CD4 and CD8 membrane markers but not the viral protein gp 70. In addition, tumor cells express IL-2 receptors and class I, but not class II, H-2 antigens. Antibodies were not detected in sera or ascitic fluid of syngeneic mice bearing a tumor transplant while both sera and ascites contained a suppressor factor that inhibited in vitro the proliferation of tumor cells and blastogenesis of normal BALB/c splenocytes after Concanavalin A stimulation. The results indicate that this tumor may be used as an experimental model for adult T cell leukemia as well as for the isolation and characterization of cytokines which may be responsible for the immunological unresponsiveness found in certain cancer patients.