cAMP plays a role in the Treg-suppressive activity of HIV infection. (A) Infected Tcons cultured alone, with untreated Tregs, or with Tregs previously treated with an inhibitor of adenyl cyclase (200uM ddADA). Tregs were loaded with calcein AM and Tcons were stained by CFSE before culture. The formation of contact between Tregs and Tcons was evidenced by the transfer of calcein from Tregs to Tcons. Data represent the percentage of infected cells in gated (CFSE⁺) Tcons after 3 days of coculture. (B) Graph showing the mean (± SEM) percentage of suppression of HIV infection in these conditions (n = 4). (C) Graph showing the MFI of CFSE, Ki67, and cyclin B staining in gated Tcons after their culture with Tregs treated or not with ddADA (n = 4).