Analysis of FOXP3 protein expression in human CD4+CD25+ regulatory T cells at the single-cell level. by Roncador, G, Brown, P, Maestre, L, Hue, S, Martínez-Torrecuadrada, J, Ling, K, Pratap, S, Toms, C, Fox, B, Cerundolo, V, Powrie, F, Banham, A