Figure 2. TMV promote differentiation of human Treg in culture.

(A) Purified CD3⁺CD4⁺ T cells were labeled with CFSE and cultured as described in Materials and Methods ± TMV or DC-derived MV (5 µg/mL). On days 3, 5 and 8, the frequency of CD4⁺CD25⁺FOXP3⁺ Treg among proliferating T cells was determined by flow cytometry. The data (means ± SD) represent three independent experiments (*p<0.01). (B) Proliferating CD3⁺CD4⁺ T cells (squares) were tested for co-expression of CD25 in a representative co-culture ± TMV. A higher proportion of proliferating CD4⁺ T cells expressed CD25 in the co-culture with TMV than without TMV. (C) The proliferating CD4⁺CD25⁺ T cells in the co-cultures with TMV were evaluated for the frequency of FOXP3⁺ T cells upon gating on the CD4⁺CD25^high subset (see box). Over 90% of these cells also expressed intracellular FOXP3. Data are representative for one out of 6 cultures tested.