Dissecting the Role of Retinoic Acid Receptor Isoforms in the CD8 Response to Infection

Vitamin A deficiency leads to increased susceptibility to a spectrum of infectious diseases. The studies presented dissect the intrinsic role of each of the retinoic acid receptor (RAR) isoforms in the clonal expansion, differentiation, and survival of pathogen-specific CD8 T cells in vivo. The data show that RARa is required for the expression of gut-homing receptors on CD8(+) T cells and survival of CD8(+) T cells in vitro. Furthermore, RARa is essential for survival of CD8(+) T cells in vivo following Listeria monocytogenes infection. In contrast, RAR beta deletion leads to modest deficiency in Ag-specific CD8(+) T cell expansion during infection. The defective survival of RAR alpha-deficient CD8(+) T cells leads to a deficiency in control of L. monocytogenes expansion in the spleen. To our knowledge, these are the first comparative studies of the role of RAR isoforms in CD8(+) T cell immunity.