Humoral immune response of mice injected with tocopherol after exposure to X-radiation.

Serum haemagglutination (HA) titers have been determined for irradiated and non-irradiated mice responding to injection of two different concentrations of sheep red blood cells (SRBC) 24 to 48 hours after irradiation and immediate intraperitoneal injection of 2.5 mg DL alpha-tocopherol, the emulsifying vehicle, or saline. Mice maintained on tocopherol-deficient diets for 8 weeks post-weaning and those on regular diets exhibited increased IgG titers during peak response when injected with vitamin E. This partially alleviated the radiation-depression of the primary immune response induced by the smaller SRBC injection. This stimulatory effect was most significant in mice maintained on vitamin E-deficient diets. The HA titers of irradiated and non-irradiated mice maintained on normal rations were determined following a 10-fold increase in the SRBC inoculation. Antibody titer was greater following injection of the higher concentration of SRBC but post-irradiation injection of tocopherol immediately or 24 hours after irradiation did not enhance immune response. At the higher SRBC concentration maximum observed HA titers decreased with increasing dose of radiation; however, tocopherol had no significant dose-reducing effect. Tocopherol toxicity as manifested by depressed HA titers was observed occasionally in non-irradiated mice challenged with the higher concentration of SRBC.