Immunological Changes during Progressive Stages of Vitamin A Deficiency in the Rat

Abstract

The immune status of rats fed a vitamin A-deficient diet (-A) was studied before they reached the weight plateau (stage 1), during the first 5 d of the weight plateau (stage 2) and during late stages of vitamin A deficiency (stage 3). Compared to vitamin A-supplemented (+A) animals, there were no significant differences in the relative splenic weights during the early and later stages of deficiency, but the total yield of isolated splenocytes was lower in -A rats during stages 2 and 3. The weights of the cervical and mesenteric lymph nodes were higher during the later stages of deficiency. In the spleen, concanavalin A (Con A)-induced responses were significantly depressed in -A rats at all three stages of deficiency. In stages 2 and 3 splenic pokeweed mitogen (PWM) responses were lower in -A than in +A rats. There were no changes in lymph node responses in stage 1. The Con A and PWM-induced responses of cervical lymph nodes of -A animals were higher in stages 2 and 3. Mesenteric lymph node responses were also higher in -A rats in stage 3. The alterations in the transformation responses of -A rats could not be explained by changes in the relative proportions of T-cell subsets.

Vitamin A Deficiency and Immunity.

“…In cervical and mesenteric lymph nodes, the lymphocyte response to mitogenic stimulation was unchanged at the early stage of the deficiency; however, responses to ConA and PWM (pokeweed mitogen) increased at the stationary and late stages of deficiency in cervical lymph nodes, and at the late stage of deficiency only in the mesenteric lymph nodes [52].…”

“…A deficiency in mice and rats did not affect lymph organ weight [51][52][53][54], except at the late stage of vitamin A deficiency at which cervical and mesenteric lymph node weights increased [52,53] The splenic lymphocyte yield (per mg of tissue) decreased in stationary and late stages of deficiency in rats (increased hematopoiesis ? ); whereas the cervical lymph node cell concentrations increased following the increase in organ weight at the late stage of deficiency; and weight, but not lymphocyte yield, increased in mesenteric lymph nodes.…”

Indicators of erythrocyte formation and degradation in rats with either vitamin A or iron deficiency

“…Vitamin A deficiency enhances the severity of infection. 29 The leukocyte composition in blood smears was as follows: basophils, 0%; eosinophils, 0.5% (range 0 -3%); band cells, 0%; polymorphonuclear cells, 15.5% (range 2-36%); lymphocytes, 84% (range 64 -98%); and monocytes, 0%. There were no systematic differences between dietary groups or between time intervals.…”

Effects of Vitamin A Deficiency on Lymphocyte Subpopulations in the Thymus, Lymph Nodes, and Spleen in Mice.

“…However, in most of these animal studies, it was difficult to separate the effects of vitamin A deficiency alone from those of more generalized protein-calorie malnutrition. In other reports, vitamin A deficiency in mice and rats did not affect lymph organ weight [12,13,15,21], except at a late stage of vitamin A deficiency at which time the cervical and mesenteric lymph node weights increased [13,15]. The splenic lymphocyte yield (per mg of tissue) decreased in stationary and late stages of deficiency in rats; cervical lymph node cell concentrations increased following the increase in organ weight at the late stage of deficiency; and weight, but not lymphocyte yield, increased in mesenteric lymph nodes.…”

“…A second factor could be the alteration of certain immune functions. Several authors reported that vitamin deficiency is responsible of functional alteration of cell-mediated immunity [12][13][14][15]. But little information is available to distinguish if this alteration is due to a quantitative (a decrease in lymphocyte number) or functional (modification in the ratio of T to B lymphocytes or between the main lymphocytes subsets) defect or both.…”