Vitamin E supplementation at various levels alters cytokine production by thymocytes during retrovirus infection causing murine AIDS.

Abstract

Female C57BL/6 mice were infected with LP-BM5 retrovirus, causing murine AIDS which is functionally similar to human AIDS. Retrovirus infection targets the thymus producing altered T-cell differentiation via the dysregulation of thymocyte cytokine production. Therefore the effects of dietary vitamin E at various levels were determined on cytokine production by ConA-stimulated thymocytes from uninfected (normal) and retrovirus-infected mice. Dietary supplementation, with a 15-, 150- and 450-fold increase of vitamin E in the diet modulated interleukin-2 (IL) production in both uninfected mice and retrovirus-infected mice. The 150- and 450-fold vitamin E supplementation significantly reduced IL-4 secretion by thymocytes from the uninfected, normal mice. Supplementation at all levels also significantly reduced IL-4 production by thymocytes, which was elevated by the retrovirus infection. Vitamin E significantly reduced IL-6 and interferon-gamma production increased during the progression to murine AIDS. The effects of dietary vitamin E on conA-induced proliferation of thymocytes were consistent with the finding on changes of IL-2 secretion. No effect of dietary vitamin E on thymus weight was observed in both uninfected and retrovirus-infected mice. These data indicate that dietary vitamin E supplementation at extremely high levels can modulate cytokine production by thymocytes. This could affect T-cell differentiation, especially during murine AIDS when cytokine production was partially normalized by vitamin E supplementation.