SUPPRESSIVE EFFECTS OF A NOVEL ANTIOXIDANT COMPOUND ON HUMAN T-CELL FUNCTIONS IN-VITRO

The use of antioxidant compounds with differing modes of action has cl early demonstrated involvement of oxidative processes in the activatio n of T lymphocytes. In this paper, we show that a novel antioxidant (l azaroid U75412E, a free radical scavenger) suppressed mitogen-induced T cell proliferation in vitro. Similar results were obtained with diph enylene iodonium (DPI), a known inhibitor of NADPH oxidase. The lazaro id was further shown to inhibit IL 2 production but to be less potent in suppressing IL 2 receptor expression. Thus, scavenger-type antioxid ants act on T cells primarily by blocking a signal necessary for the i nduction of IL 2 synthesis such as the activation of NFkappaB. Further more, the potent inhibition of lymphocyte responses caused by the spec ific enzyme inhibitor DPI provides direct proof of the source of the o xidants involved in these processes.