EFFECTS OF VITAMIN B6 DEFICIENCY ON LYMPHOID TISSUES AND HUMORAL IMMUNE RESPONSE IN RATS (IMMUNITY, PYRIDOXINE)
Abstract
The influence of vitamin B(,6) deficiency on lymphoid tissues and humoral immune response in rats was assessed in two experiments. In experiment I effects of vitamin B(,6) deficiency on humoral immune response and morphological changes of sensitized lymphoid tissues were studied in growing rats. Male weanling rats (Sprague-Dawley) were divided into three treatment groups: control, restricted control and vitamin B(,6) deficient. Animals in control and vitamin B(,6) deficient groups were fed for 8 wk ad libitum a basal diet supplemented with 7 or 0 mg pyridoxine-HCl(PN-HCl)/kg, respectively. The restricted control group was fed the control diet (7 mg PN-HCl/kg) but restricted in amount to that consumed by the vitamin B(,6) deficient group on the previous day. At 7 wk, formalinized Streptococcus mutans was administered intraperitoneally. Antibody titers against S. mutans, measured by microagglutination test at 9 wk, were significantly lowered by vitamin B(,6) deficiency. Activities of IgM and IgG antibody were low in the deficient group and lymphocyte depletion was observed in thymus and paracortical regions of ileic lymph nodes. Immunized deficient rats showed no germinal centers or poorly developed ones in lymph nodes indicating their inability to respond normally to an antigenic stimulation. In experiment 2, the effect of maternal vitamin B(,6) deficiency on the developing immune system in rats was studied. Female rats (Sprague-Dawley) were fed diets containing 7, 0.6, 0, or 7 mg pyridoxine-HCl (PN-HCl)/kg during gestation and 7, 0.6, 7, or 0 mg PN-HCl/kg during lactation (groups C, MGL, DG and DL). Severe deficiency during gestation adversely affected thymus and spleen sizes of 2-day-old pups. Marginal restriction of vitamin B(,6) imposed on dams throughout gestation and lactation resulted in extremely low weights of thymus and spleen in 20-day-old pups. Severe restriction of vitamin B(,6) during lactation affected spleen weight more than thymus. After weaning, pups in groups, C, MGL, DG, and DL were fed diets containing 7, 0.6, 7, and 7 mg PN-HCl/kg, respectively. On day 42, pups of the MGL group had smaller thymuses and spleens. After 3 or 6 wk of vitamin B(,6) supplementation, weights of lymphoid tissues were restored to controls but the functional ability of ileic lymph nodes to respond to an antigenic stimulation remained impaired. Dietary restriction of vitamin B(,6) during either gestation or lactation did not significantly affect the humoral immune response of progeny. However, marginal restriction of vitamin B(,6) throughout gestation and lactation of dams and during a 21-day postweaning period of their pups resulted in depressed antibody titers of pups immunized with S. mutans.
Degree
Ph.D.
Subject Area
Nutrition
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