Vitamin E supplementation normalizes immune dysfunction in murine AIDS induced by LP-BM5 retrovirus infection

It is known that murine AIDS, induced by i.p. injection of LP-BM5 retrovirus, is functionally similar to human AIDS. In this study, we tried to examine the effect of vitamin E (dl-α-tocopheryl acetate) supplementation on the decrease of cellular immune functions following the development of murine AIDS. Female C57BL6 mice, 4 weeks old, were infected with LP-BM5 retrovirus and then fed control (50 IU/kg diet) or high vitamin E (500 or 2500 IU/kg diet) diets for 10 weeks. The spleen weight and number of splenocytes were largely increased following the development of murine AIDS. On the contrary, vitamin E supplementation suppressed the enlargement of spleen and the increased number of splenocytes following retrovirus infection. The decrease of NK activity shown in mice infected with LP-BM5 retrovirus was also partly improved by high vitamin E diet. Proliferation of splenic T lymphocytes, showing the marked decrease following murine AIDS, was significantly restored by higher vitamin E (2500 IU/kg diet) diet compared to control group, which was still lower in comparison with that of uninfected control group. Furthermore, vitamin E supplementation increased production of interferon-γ (IFN-γ) and suppressed production of tumor necrosis factor-α (TNF-α) from splenocytes. In addition, high vitamin E diet also decreased the increased ratio of CD4 and CD8 single positive T cells following the development of murine AIDS, which was almost equal to the levels of uninfected control and high vitamin E groups. These results suggest that vitamin E supplementation normalizes the decrease of immune functions following the development of murine AIDS.