RAG2 and colitis: Using this approach, we tested the capacity of MP cell subpopulations to induce colitis by individually transferring CD127hi Sca1lo, CD127hi Sca1hi, CD127lo Sca1hi, and CD127lo Sca1lo Foxp3− MP CD4+ T cell subsets from Foxp3-reporter mice to Rag2 KO recipients.