HIV-exposed Treg cells maintain strong suppressive activity. Purified CD4⁺CD25⁺ T cells were cultured in presence of AT-2 HIV, or microvesicles. At day 4, cells were mixed with CFSE-labeled autologous CD4⁺CD25^– T cells, and stimulated with PHA for 3 days in presence of APCs. Effector T cells were also cultured with PHA and APCs (PHA), and with APCs alone (unstim). Numbers indicate the percentages of effector cells that had undergone at least one division cycle. Results from 1 donor, representative of 3, are shown.