Phenotypic and functional characteristics of mononuclear cells in ovarian carcinoma tumors

By using monoclonal antibodies and flow cytometry, the phenotype and activation state [based on presence of interleukin 2 (IL-2) receptors] were determined on the mononuclear cell (MNC) fraction of ovarian carcinoma tissue from 12 patients. Thymidine incorporation response to IL-2 and phytohemagglutinin stimulation was measured in five cases. By FACS analysis, tumor MNCs contained 79% T cells, 11% monocytes/macrophages, 5% B cells, and 5% natural killer cells. Similar findings were noted in the patients' peripheral blood MNC population. The respective T-helper:cytotoxic/suppressor ratios in tumor and blood MNC populations were less than 1 and approximately 2. The percentage of IL-2 receptor-positive cells was low in both populations. The proliferative response of tumor MNCs was lower than that of blood MNCs from patients and from normal volunteers. These results suggest an intratumor immune suppression, perhaps secondary to the absence of a specific responder population or to the presence of suppressor cells or a soluble factor secreted by the tumor that directly suppresses or affects MNC transport into and out of the tumor.