Differential effect of alpha-tocopherol and ascorbate on oxidative injury induced in immune cells by thermal stress.

As immune cells are often subjected to hyperthermia that can easily occur either after intense and/or prolonged exercise or during defense against pathogens, in this paper we analysed whether superoxide anion production occurred in lymphocytes exposed to high temperature and, consequently, if antioxidants could exert any protective function. The results demonstrated that an increase of superoxide anion was induced in rabbit lymphocytes exposed to 42 degrees C for 1h, although cell viability was no affected. However, suppression of either Pokeweed mitogen (PWM)-driven cell proliferation, or immunoglobulin production or IL-2 synthesis was observed. To evaluate the capacity of antioxidants to restore the immune suppressed responses, two vitamins, alpha-tocopherol and ascorbic acid, were added to PWM-stimulated cultures following heat treatment. The data demonstrated that alpha-tocopherol was able to totally abrogate the inhibitory effects mediated by thermal stress, while ascorbic acid did not give any protective results.