TMV promote differentiation of human Treg in culture.

<p>(<b><u>A</u></b>) Purified CD3⁺CD4⁺ T cells were labeled with CFSE and cultured as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011469#s4" target="_blank">Materials and Methods</a> ± 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><u>B</u></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. (<b><u>C</u></b>) 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.