Retinoic Acid An Educational “Vitamin Elixir” for Gut-Seeking T Cells

AbstractT cell priming by dendritic cells (DC) from gut-associated lymphoid tissues gives rise to effector cells with pronounced gut tropism. The mechanism for DC-dependent imprinting of gut specificity has remained unknown. New findings point to retinoic acid, which is uniquely produced by intestinal DC, but not by DC from other lymphoid organs (Iwata et al., 2004; this issue of Immunity)