Protective effects of supplemental vitamin E against infection.

Vitamin E supplementation (dl-alpha-tocopheryl acetate except where noted) in excess of requirement significantly increased humoral immune response or disease resistance. Mice immunized with sheep red blood cells or tetanus toxoid and fed the supplemental vitamin demonstrated increased plaque-forming cells (PFC) and hemagglutinin (HA) titers. A vitamin E deficiency resulted in decreased PFC and little IgG which was partially corrected by N,N-diphenyl-p-phenylenediamine but not as effectively as by vitamin E. Hens immunized with Brucella abortus and fed different levels of the vitamin produced chicks with increased passive immunity; a biphasic antibody response to the level of the vitamin fed was noted. Vitamin E fed to nonimmunized hens was found to significantly increase the primary immune response of their immunized chicks. Feeding dl-alpha-tocopheryl acetate to guinea pigs immunized with Venezuelan equine encephalomyelitis virus resulted in no increased immunity. Injecting this form of the vitamin resulted in severe tissue reaction. However, injecting dl-alpha-tocopheryl significantly improved hemagglutinin inhibition titers. Chicks and turkeys infected with Escherichia coli and fed supplemental vitamin E had reduced mortality and increased HA titers. Sheep fed vitamin E and challenged with Chlamydia had improved weight gains and no detectable Chlamydia.