To determine whether membrane cholesterol enrichment by in vivo squalene administration alters the reactivity of antigen-specific (HA110–120) Th1 cells in vivo, we took advantage of a RAG2 KO, RIP-HA Tg mouse model in which autoimmune diabetes (type 1 diabetes, T1D) is induced by i.p. infusion of splenic CD4 T-cells (2.5×105 cells) from TCR-HA Tg mice. Here, RAG2 is linked to type 1 diabetes mellitus.