ABSTRACT
Lamina propria dendritic cells (DCs) have a permanent turnover with constitutive migration to mesenteric lymph nodes and replenishment by progenitors. Luminal bacteria and dietary constituents provide key signals that endow DCs their unique properties in vivo. Taking into account that the intestinal immune system is greatly influenced by retinoids, we evaluated in B6 mice 3, 8, 16 and 24 h after feeding a single dose of vitamin A phenotype and function of cells present in mesenteric afferent lymph nodes as well as signals involved in migration. We studied the frequency of CD11c+MHC-II+CD103+CD86+ and RALDH+ DCs by flow cytometry, we determined CCL-21 and D6 levels in tissue homogenates by Western blot, and we co-cultured cells isolated from afferent lymphatics with sorted CD4+ lymphocytes to assess Foxp-3 induction and homing receptor expression. Sixteen hours after vitamin A administration, DCs isolated from afferent lymphatics were able to induce homing receptors and Foxp3 expression in CD4+ lymphocytes. Our results show that a single dose of vitamin A generated a stream of signals and amplified the tolerogenic activity of DCs migrating to lymphoid tissue.