Interleukin-2 stimulation activates mesothelial cellular functioning against autologous tumor cells.

BACKGROUND The present study was designed to determine the different effects of cytokines or antibodies (IL-2, IL-4, IL-7, IL-10, IL-12, alphaCD3) in stimulating the cellular functions of mesothelial cells isolated from malignant pleural effusion. METHODS Mesothelial cells were isolated from 27 patients with malignant pleural effusion. The cultured cellular interferon-gamma (IFNgamma) and IL-10 production, proliferative response, and cytolytic activity against autologous tumors and K-562 cells were measured. RESULTS Stimulation with IL-2 alone significantly increased the mesothelial cells' proliferative response (p < 0.001) and cytolytic activity against autologous tumors (p = 0.025). The further addition of other cytokines did not increase these functions. The IFNgamma/IL-10 ratio data showed that the T-helper (Th) pathway was shifted from the Th-2 pathway to the Th-1 pathway (increase of IFNgamma/IL-10 ratio) when mesothelial cells were stimulated with IL-2. Further stimulation with IL-2 plus IL-12 or alphaCD3 shifted the Th pathway further in the Th-1 direction, but without statistical significance. CONCLUSIONS The mesothelial cell proliferative response is enhanced with IL-2 stimulation alone. The T-helper pathway is also shifted from the Th-2 to the Th-1 response (increase of IFNgamma/IL-10 ratio) after IL-2 stimulation of mesothelial cells. Mesothelial cells had cytolytic activity against tumor cells, and this activity could be augmented by IL-2 stimulation.