CD4 and lymphopenia: To further confirm that rTsPmy could not induce the de novo generation of pTregs under inflammatory conditions, we adoptively transferred CD45RBhiFoxp3–CD4+ naïve T cells from Foxp3eGFP reporter mice into T/B lymphocyte-deficient Rag1 KO mice to induce T-cell-mediated inflammation in the colon (Chen et al., 2017), followed by treatment with rTsPmy to assess the differentiation of pTregs in colon in lymphopenia/inflammation.