Involvement of the 55- and 75-kDa tumor necrosis factor receptors in the generation of lymphokine-activated killer cell activity and proliferation of natural killer cells.

In this study we investigated the expression of the 55 kDa (p55) and the 75 kDa (p75) TNF receptors in CD56+ NK cells and their role in NK and lymphokine-activated killer cells cell functions. By using mAb against the p55 and p75 TNF-R, NK cells were found to express both p55 and p75 upon activation, and both receptors were involved in the generation of lymphokine-activated killer cells activity. Proliferative activity of IL-2 stimulated NK cells was inhibited by anti-TNF-alpha mAb, indicating that endogenously produced TNF-alpha is important for optimal proliferation of NK cells. Furthermore, addition of rTNF-alpha increased the IL-2-induced proliferation of NK cells. mAb to p55 and p75 inhibited the IL-2-induced proliferation indicating that both TNF-R are involved in mediating this effect.