CD4 and Hyperglycemia: The RAG2 KO, RIP-HA Tg recipients developed hyperglycemia by 8–10 days after cell transfer, whereas those receiving either CD4+ (Foxp3-GFP) +/− T-reg cells from the same F1 donors or CD4 splenic T-reg cells from Foxp3-GFP+/+ Tg parental mice did not (Figure 7A).