Tat protein does not affect the viability of purified CD4 T-cells.

<p>Purified CD4 T-cells from healthy HIV-negative volunteers (n = 4) were incubated in medium alone or with Tat protein (10 µg/ml) for up to 72 hours and then stained with propidium iodide or annexin V-FITC and analyzed by flow cytometry. Analyses were performed on the total ungated population as well as on only live cells based on forward and side scatter. (A) Propidium iodide exclusion showed no significant difference in viability between cells cultured in Tat or medium alone. (B) Apoptosis as indicated by positive annexin V staining averaged <10% in the gated population at 72 hours and was no different comparing cells cultured in medium alone or with Tat protein. Camptothecin (10 µM) induces apoptosis and was used as a positive control. * denotes p value <0.05 compared to media. Graphs show mean values ± SEM.