FIG. 3.

Production of IL-10 by monocytes stimulated by Tat immobilized in wells. (A) Tat was immobilized in wells by incubation for 2 h at 37°C. After two washes to eliminate nonfixed Tat, monocytes (10⁶) were added and cultured for 24 h with different concentrations of Tat (5, 50, or 500 nM). Culture supernatants were recovered, and the presence of IL-10 was determined by ELISA. (B) HeLa P4 cells were incubated with soluble (solid bars) or immobilized (shaded bars) Tat, and a Tat-dependent-transactivating test was done as described in Materials and Methods. The values are the means ± SD of three experiments. For A, similar results were obtained with cells from two different donors.