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4 Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111 and 5 Department of Pathology, Sackler Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111
Supplemental vitamin E alleviates age-related defects in interleukin (IL)-2 production, T cell proliferation, and immune synapse formation. Here, we evaluated the effect of in vitro supplementation with 46 µmol/L of vitamin E on T cell receptor-proximal signaling events of CD4+ T cells from young (4–6 mo) and old (22–26 mo) C57BL mice. Aged murine CD4+ T cells stimulated via CD3 and CD28, tyrosine 191 of the adaptor protein Linker for Activation of T cells (LAT), was hypo-phosphorylated. Supplementation with vitamin E eliminated this difference in the tyrosine phosphorylation of LAT. By using a flow cytometric assay, the age-related differences in the activation-induced phosphorylation of LAT were observed in both naïve and memory T cell subsets. In addition, supplementation with vitamin E eliminates the age-related differences in LAT phosphorylation in both T cell subsets. Neither age nor vitamin E supplementation altered the fraction of LAT entering the membrane compartment. Furthermore, neither age nor vitamin E influenced the phosphorylation of Lck and Zap70, indicating that associated changes in LAT phosphorylation were not caused by alterations in activation states of the upstream kinases Lck and Zap70.
* To whom correspondence should be addressed. E-mail: simin.meydani{at}tufts.edu.
Manuscript received 11 December 2008. Initial review completed 5 January 2009. Revision accepted 1 April 2009.
Published online 29 April 2009.