In Vitro Effects of β-Carotene and Vitamin A on Peripartum Bovine Peripheral Blood Mononuclear Cell Proliferation

Abstract

The effects of β-carotene, retinol, and retinoic acid on function of mononuclear cells during the peripartum period was assessed in vitro. Blood was collected from 14 Holstein cows on wk –4, –1, 0, 1, and 4 postpartum, and mononuclear cells were obtained by gradient centrifugation. Mononuclear cell proliferation induced by concanavalin A was measured in the presence of β-carotene, retinol (1 × 10–9 and 1 × 10–8M), and retinoic acid (1 × 10–10 and 1 × 10–9M). Retinol and β-carotene had no effect on spontaneous cell proliferation, whereas retinoic acid was suppressive. However, 1 × 10–9M β-carotene enhanced concanavalin A-induced proliferation at wk –1, whereas 1 × 10–8M β-carotene was suppressive at wk –4. Retinoic acid suppressed concanavalin A-induced proliferation at wk 0, but retinol had no effect. These results suggest a mechanism by which β-carotene affords the mammary gland protection against infection immediately prepartum.