Fig. 4: Retinoic acid-producing dendritic cells facilitate the differentiation of IgA + B lymphocytes within the mesenteric lymph nodes in a T cell-dependent fashion.
From: The role of retinoic acid in the production of immunoglobulin A
Antigen-loaded tolerogenic dendritic cells (DCs) migrate from the lamina propria (LP) into the mesenteric lymph nodes (MLNs) via lymphatic vessels. In the MLNs, luminal antigens are recognized by the B cell receptor on naïve B lymphocytes, which together with T cell help, initiates B cell activation. Moreover, RA initiates the expression of the gut-homing molecule α4β7 on B and T lymphocytes. Subsequently, when activated B cells leave the MLNs, they move towards the circulation, after which they travel to the LP using α4β7 and populate this site as IgA-secreting plasma cells. T cell-independent B cell activation has also been reported but described to not be the predominant process in the MLNs.
