THIOL SUPPLIER N-ACETYLCYSTEINE ENHANCES CONJUGATE FORMATION BETWEEN NATURAL-KILLER-CELLS AND K562 OR U937 TARGETS BUT INCREASES THE LYTIC FUNCTION ONLY AGAINST THE LATTER

In this in vitro study, an evaluation of the importance of intracellul ar oxidative balance on cell-mediated cytotoxicity was performed by an alyzing the effects of the antioxidant N-acetylcysteine (NAG), a speci fic thiol supplier, on natural killer (NK) cell-mediated cytotoxicity. The results obtained indicate that an enhancement of target cell (TC) killing can be detected when a pre-exposure of effector cells (EC) to NAC was performed. However, this effect seems to depend upon the TC t ype used. In fact, the increase of EC activity was detected against th e differentiated U937 TC while no changes were detected by the same ef fecters against K562 cells. The mechanism of this enhancement seems to be ascribable to an increased ability of NAG-exposed NK cells to form conjugates (binding) which, in turn, appears to be due to a specific effect of NAC on actin microfilaments. A role for NAC as a cytoskeleto n thiol-modifier contributing to the activation of effector cells can thus be hypothesized.