The retinoid-related orphan receptor gamma (RORgamma) is a member of the nuclear receptor superfamily. NIH investigators used homologous recombination in embryonic stem cells to generate mice in which the RORgamma gene was disrupted. RORgamma deficient mice lack peripheral and mesenteric lymph nodes and Peyer's patches indicating that ROR expression is indispensable for lymph node organogenesis. In addition, RORgamma is required for the generation of Th17 cells which play a critical role in autoimmune disease.

The RORgamma deficient mice are useful to identify the physiological functions of the RORgamma. RORgamma deficient mice also provide an excellent tool to study the role of RORgamma in immune responses and autoimmune disease, the study of the role of Th17 and interleukin 17 in these processes, and the analysis.