Induction of immunocellular resistance to IL-2-activated lymphocytes within ovarian carcinoma cells

The development of resistance within ovarian carcinoma cells to activated cytotoxic lymphocytes was the objective of this study. Primary ovarian carcinoma cells were obtained from the ascites of a patient. These cells were cocultured with IL-2-activated autologous tumor-associated lymphocytes (TALs) for 1 week. The resulting selected cells underwent a second coculture for 3 days with IL-2-activated autologous TALs or tumor-infiltrating lymphocytes (TILs). Phenotype analysis of the lymphocytes was performed prior to selection and 4-hr chromium release assays were used to detect resistance induction. Resistance to all effector cells could be demonstrated for the selected cells. However, selected cells maintained in culture demonstrated no difference in cytotoxic susceptibility from unselected cells. The following conclusions were made: (i) rapid immunoselection can occur for ovarian carcinoma in vitro; (ii) the resistance induced is not MHC-restricted; (iii) resistance induced by one type of cytotoxic cell results in general resistance to other types of cell from the same patient; and (iv) this resistance is not maintained during in vitro culture. These results may have direct implications on the future immunotherapy for this condition.