Vitamin C enters mouse T cells as dehydroascorbic acid in vitro and does not recapitulate in vivo vitamin C effects

Vitamin C is an essential micronutrient, which has been implicated in various biological processes, including immune response. In fact, in vivo administration of vitamin C modulates T cell proliferation and cytokine secretion. In this study, we analyzed the mechanism by which mouse T cells take up vitamin C, and whether this uptake directly affected T cell functions. T cells internalized more vitamin C when they were activated, due to enhanced glucose transporter (GLUT)-1 and GLUT-3 expression that persisted up to 48h after activation. Blocking oxidation of ascorbic acid (the reduced form of vitamin Q in the culture medium with 1,4-dithio-threitol (DTT) almost completely inhibited the enhanced vitamin C uptake. The presence of vitamin C at low concentrations during in vitro T cell activation did not affect proliferation or cytokine secretion (IFN-gamma, TNF-alpha, or IL-4) in response to PMA/ionomycin. In contrast, high concentrations (0.25-0.5mM) of vitamin C lowered cell viability, reduced thymidine uptake, and decreased cytokine secretion. In conclusion, activated T cells upregulated GLUT-1 and -3 to increase vitamin C uptake. They took up vitamin C mostly in its oxidized form, rarely in its reduced form. Application of vitamin C to T cells in vitro did not recapitulate previously reported in vivo responses to vitamin C, suggesting that in vivo, vitamin C modulates T cells indirectly through other components of the microenvironment.Maratou E, 2007, EUR J CLIN INVEST, V37, P282Mazzoni A, 2006, J IMMUNOL, V177, P3577Wintergerst ES, 2006, ANN NUTR METAB, V50, P85, DOI 10.1159/000090495PEARCE EJ, 2006, CHEM IMMUNOL ALLERGY, V90, P82Noh K, 2005, IMMUNOL LETT, V98, P63, DOI 10.1016/j.imlet.2004.10.012de Jong EC, 2005, SPRINGER SEMIN IMMUN, V26, P289, DOI 10.1007/s00281-004-0167-1Hartel C, 2004, CYTOKINE, V27, P101, DOI 10.1016/j.cyto.2004.02.004Mazzoni A, 2004, J LEUKOCYTE BIOL, V75, P721, DOI 10.1189/jlb.1003482Hosoya K, 2004, INVEST OPHTH VIS SCI, V45, P1232, DOI 10.1167/iovs.03-0505Patak P, 2004, ENDOCR RES, V30, P871, DOI 10.1081/ERC-20044126Fu YC, 2004, BLOOD CELL MOL DIS, V32, P182, DOI 10.1016/j.bcmd.2003.09.002Matsue H, 2003, J IMMUNOL, V171, P3010Nualart FJ, 2003, J BIOL CHEM, V278, P10128, DOI 10.1074/jbc.M210686200DETULLIO MC, 2002, VITAMIN C FUNCTION B, P159Maldonado-Lopez R, 2001, SEMIN IMMUNOL, V13, P275, DOI 10.1006/smim.2001.0323Baoutina A, 2001, FASEB J, V15, P1580, DOI 10.1096/fj.00-0704fjeClement MV, 2001, ANTIOXID REDOX SIGN, V3, P157Rumsey SC, 2000, J BIOL CHEM, V275, P28246Campbell JD, 1999, CELL IMMUNOL, V194, P1Tsukaguchi H, 1999, NATURE, V399, P70Verhasselt V, 1999, J IMMUNOL, V162, P2569Long KZ, 1999, PEDIATR INFECT DIS J, V18, P283Tatla S, 1999, FREE RADICAL BIO MED, V26, P14Lykkesfeldt J, 1999, METHOD ENZYMOL, V299, P83Podmore ID, 1998, NATURE, V392, P559Vera JC, 1998, BLOOD, V91, P2536Rumsey SC, 1997, J BIOL CHEM, V272, P18982Ngkeekwong FC, 1997, BIOCHEM J, V324, P225EYLAR E, 1996, P R HEALTH SCI J, V15, P21JEANNIN P, 1995, J EXP MED, V182, P1785VERA JC, 1995, J BIOL CHEM, V270, P23706VERA JC, 1994, BLOOD, V84, P1628VERA JC, 1993, NATURE, V364, P79BERGSTEN P, 1990, J BIOL CHEM, V265, P2584VANDERJAGT DJ, 1987, AM J CLIN NUTR, V46, P290KENNES B, 1983, GERONTOLOGY, V29, P305OKAMURA M, 1980, CLIN CHIM ACTA, V103, P259ANDERSON R, 1980, AM J CLIN NUTR, V33, P71Roe JH, 1943, J BIOL CHEM, V147, P399