[Defects in cell-mediated and humoral immunity in tumor-bearing mice. Evidence and characterization of suppressor cells]

Abstract

The immune response of mice bearing a transplantable tumor which was induced by Benzyprene was studied. The humoral response to sheep red blood cells (hemolytic plaque assay) is increased until the day 18 after inoculation of the tumor if calculated in relation to the total number of spleen cells, but it is decreased related to 10(6) spleen cells after day 9. Because the weight of the spleen increases during this time this result suggests that the relation between antibody producing and nonproducing cells becomes smaller, despite the total number of antibody producing cells is higher. The unspecific suppression of the cell-mediated immune response in vivo was was studied by the adoptive transfer of spleen cells from tumor bearing mice and allografting of the recipients. The rejection of the grafts is delayed. The stimulation of spleen cells with PHA is smaller with cells from tumor animals than in controls. The fraction which is nonadherent on glass beads has a higher reactivity than the total population, this difference is more distinct in tumor animals. The suppressor cells from tumor mice are glass adherent and their activity is negatively influenced by treatment of the tumor mice with Carageenan.