Vitamin A deficiency impairs induction of oral tolerance in mice

Abstract

Oral tolerance is a phenomenon of induction of systemic unresponsiveness to antigens ingested by the oral route and loss of immune response. Studies have shown the importance of vitamin A in oral tolerance in vitro but not in an in vivo experimental model. Therefore, we carried out experiments to determine how vitamin A deficiency affects tolerance induction and the ability of mesenteric lymph node (MLN) CD11c+ cells to induce regulatory T cells (Tregs). Immunological tolerance was induced by oral ovalbumin (OVA) administration in vitamin A-sufficient mice. OVA-specific antibody and cytokine production were significantly reduced. On the other hand, in vitamin A-deficient mice, both OVAspecific antibody and cytokine production were not suppressed by oral OVA administration. Regarding induction of Tregs, the conversion rate of Foxp3+ cells from naïve CD41 cell by CD11c+ cells was decreased in vitamin A-deficient mice. Our study indicates that vitamin A deficiency causes the breakdown of oral tolerance in vivo.