The relative resistance of lymphokine activated killer cells to suppression by prostaglandins and glucocorticoids.
The possibility that lymphokine-activated killer (LAK) cells versus spontaneous natural killer (NK) cells show relative resistance to the suppressive effects of the immunoregulatory molecules prostaglandin E2 (PGE2) and dexamethasone (DMO) was investigated. LAK cells were produced in vitro by the incubation of human peripheral mononuclear cells (PBMC) for three days in the presence of interleukin-2 (IL-2). Cytotoxicity of NK and LAK cells were measured by conventional 4 hour Cr51 release assays using K562 and Daudi target cells. LAK cells were relatively resistant to suppression by PGE2. For example, NK cytotoxicity was significantly suppressed by 10(-6) M PGE2. In contrast, LAK cells required a 30 to 100 higher concentration of PGE2 according to the target used to achieve similar suppression. Likewise, a differential resistance to DMO was seen. NK cells were significantly suppressed by 10(-3) M DMO while a 1000 fold higher concentration was needed for similar suppression of LAK cytotoxicity. Overall, the results show that LAK cells are relatively resistant to immunoregulatory suppressive factors.