R2G2模型是一种双敲除鼠标，具有超免疫缺陷表型。该模型是通过回交的IL2RG.(common gamma chain) mutation on to a mixed background mouse (C57BL/6 and129 mix) with a mutation inRag2. The recombination activating gene 2 (Rag2) interruption causes a deficiency in T and B cells. The Common gamma chain gene (IL2RG.) interruption results in a lack of functional receptors for IL-2, IL-4, IL-7, IL-9 and IL-15.

Envigo acquired from Fox Chase Cancer Center in 2016, where the model had been maintained since 2005. The model is a white-bellied, light chinchilla (light tan).