I am using miltenyi biotec for isolation of CD4CD25 Treg cells....

I am using now your protocol however on IL4 staining I am getting a significant shift in my sample compared to unstained control but no separate distinction of a positive versus negative population. What I am doing now is just adding the antibody in the perm buffer. I am using 11B11 antibody from Biolegend (504104) for flowcytometric analysis.

N.B. I am getting ~75% positive cells for INfg after Th1 differentiation!!

Regards

Tamer

Sorry I haven't use this technique before, but I think CD44 and CD62L test are still necessary for the naive phenotype. Although some resting memory cell express CD25, there are CD25- effector and memory cells. I did not use CD4+CD25- population as the naive T cells, so cannot answer the purity question.