Naturally occurring Treg suppress Teff proliferation, but do not induce apoptosis.

<p>Cells were cultured in 200 µl medium for 5 days (n = 3). (A) Proliferation of Teff measured by flow cytometry, cultured alone (left) or in co-culture with naturally occurring Treg (1-1) (right). 1 representative example is shown. (B) Level of suppression of Teff proliferation, calculated for several ratios of Teff + Treg, and Teff + Teff (ratio 1-1), compared to culture of Teff alone (suppression = 0%). (C) Apoptotic Teff cells (CFSE<sup>+</sup>) were measured after 7-AAD and Annexin V staining by flow cytometry analysis. Percentage of apoptosis in Teff cultured alone (left) and in co-culture with Treg (1-1) (right). 1 representative example is shown. (D) Average percentage, and (E) absolute number, corrected for cell input, of apoptotic Teff expressing 7-AAD and Annexin V, for several co-culture ratios of Teff + Treg, Teff + Teff (1-1) and Teff alone,. Cells were cultured in 75 µl medium for 5 days (n = 9). (F) Level of suppression of Teff proliferation, calculated for several ratios of Teff + Treg, and Teff + Teff (ratio 1-1), compared to culture of Teff alone (suppression = 0%). (G) Average percentage, and (H) absolute number, corrected for cell input, of apoptotic Teff cells expressing 7-AAD and Annexin V, for several co-culture ratios of Teff + Treg, Teff + Teff and Teff alone (n = 9). Error bars represent means±s.e.m., * P<0.05, # P<0.01, ▒ P<0.001.</p>