Mononuclear leukocytes from mice with resected tumor induce resistance to transplantation of tumor cells to animals.

Experiments on male C57Bl/6 mice with intraperitoneally transplanted Ehrlich carcinoma and DBA/2 mice with subcutaneously transplanted S-91 melanoma showed that preliminary injection of mononuclear leukocytes obtained from animals 6-8 h after tumor resection induce resistance to transplantation of malignant transformed cells. Our results suggest that not only humoral factors, but also immunocompetent cells are involved in the regulation of tumor growth. The resistance to tumor transplantation was not induced by mononuclear leukocytes isolated over the first hours and 10-12 h after removal of the primary tumor node, which excludes the direct cytotoxic effect of these cells and suggests that this phenomenon is not associated with activation of the effector mechanisms for innate and adoptive immunity.

[Peripheral blood lymphocytes in melanoma].

In 20 patients with melanoma and 8 healthy donors the number of lymphocytes binding type-specific immunoglobulin in peripheral blood was determined by the method of direct immunoluminescence. The content of B-and T-lymphocytes was calculated. The results obtained made it possible to find some regularities with respect to the cell concent of lymphocytes population in patients with melanoma.