The impact of vitamin a deficiency and repletion with retinol and β-carotene on concanavalin a-induced lymphocyte proliferation

Concanavalin A (Con A)-induced splenic lymphocyte proliferation was studied in young rats during vitamin A deficiency and after oral repletion with 1500 retinol equivalents (R.E.) of either retinyl palmitate (RP) or βC-carotene (βC). Initial studies, designed to optimize the proliferation assay, showed that the response of vitamin A-deficient rats was consistently delayed in comparison to control rats fed a vitamin A-adequate diet. The overall magnitude of the proliferative response in vitamin A-deficient rats was also somewhat reduced (≈34% less than that of the control group). After vitamin A-deficient rats were repleted with RP, the Con A-induced proliferative response of splenic lymphocytes resembled that of the control group in both magnitude and kinetics. However, in vitamin A-deficient rats repleted with βC, the delayed response to Con A persisted in some animals and the overall response was intermediate between that of vitamin A-deficient rats and either control rats or rats repleted with RP.