Regulation by Glutathione of the Activation and Differentiation of IL-4-Dependent Activated Killer Cells

Glutathione (GSH) was shown to regulate the generation of IL-2-dependent activated killer cells. Generation of αCD3-activated killer cells CD3-AK was regulated by both IL-2 and IL-4. In the present study the role of GSH in the regulation of IL-4-dependent CD3-AK cells was examined. After initial activation of mouse splenocytes by αCD3, subculturing the CD3-AK cells in IL-4 resulted in the production of IL-4-dependent killer cells whose proliferative and cytolytic activities were abrogated by αIL-4 antibody 11B11. Adding graded doses of BSO, a GSH synthetase inhibitor, into CD3-AK cells culturing in IL-4 resulted in the reduction of their proliferative and cytotoxic responses. Adding exogenous GSH reversed the inhibitory effect of BSO and restored the proliferation and cytolytic activity of IL-4-dependent CD3-AK cells. The dose requirement for BSO to affect the IL-4-dependent CD3-AK cells was similar to that for the IL-2-dependent CD3-AK cells. These findings indicate that GSH also regulates the function of IL-4 in the activation and differentiation of CD3-AK cells. To further study the mechanism for the GSH regulation of the cytolytic activity of CD3-AK cells, we found that BSO did not reduce the production of BLT-esterase which contained mostly the cytolytic granules; in fact, BLT-esterase production was often increased by BSO. Furthermore, the exocytosis and effector function of cytolytic granules were also not affected by BSO. Thus it appears that reduction of cellular GSH may result in the accumulation of defective cytolytic granules which accounts for the reduction of killer cell cytolytic activity.