Regulation of CD8⁺ T cell functions by RARγ

Retinoic acid plays a key role in the development and function of the immune system; however, the contribution of each of the three retinoic acid receptors (RARs) to the T cell immune response is not yet well understood. Of these receptors, both RARα and RARγ are expressed in T lymphocytes. While possible functional redundancy thus complicates understanding of the role of each receptor in T cells, emerging data suggest that RARα and RARγ function differently in thymocyte development and that RARγ is required for both primary and secondary CD8⁺ T cell immune responses.