Effect of vitamin E deficiency on the proliferative response of canine lymphocytes

The effect of vitamin E deficiency on the proliferative response of canine lymphocytes was examined, using the lymphocyte blastogenesis assay, with phytohemagglutinin, concanavalin A, and pokeweed as mitogenic stimulants. A litter (4 pups; group 3) from a bitch fed a complete diet was given a complete diet from the time of weaning (6 weeks) until termination of the experiment, and served as a control group. A litter (4 pups; group 1) from a bitch fed a vitamin E-deficient diet was given a vitamin E-deficient diet from the time of weaning (6 weeks) until termination of the experiment. A litter (6 pups; group 2) from a bitch fed a complete diet was weaned onto a complete diet and then changed to a deficient diet until termination of the experiment. Lymphocytes from group 1 and 2 pups (fed deficient diets) were poorly responsive to mitogen-induced blastogenesis, compared with the lymphocytic response seen in the controls. Washing the lymphocytes from the pups fed vitamin E-deficient diet resulted in enhanced responsiveness to mitogen stimulation. Lymphocytes from controls which had good responses when cultured in bovine fetal serum or normal canine serum were poorly responsive when cultured in serum from groups 1 and 2 pups (fed vitamin E-deficient diet). Reducing the concentration of group 1 and 2 pup sera in the culture medium restored the responsiveness of lymphocytes from control pups. Supplementation of group 1 and 2 pup sera with bovine fetal serum did not result in enhancement of the responses of lymphocytes from controls. The capability of sera from vitamin E-deficient pups (groups 1 and 2) to support blastogenesis of lymphocytes from control dogs was restored following dietary supplementation with vitamin E. It was concluded that the depressed lymphocyte responsiveness in pups fed vitamin E-deficient diet was due to the presense of a suppressive factor in the serum.