FIG. 2.

Specificity of Tat-induced IL-10 production and mapping of the active domain. (A) Monocytes (10⁶) were incubated with wild-type GST-Tat 1-101 (1 or 10 nM) or with recombinant mutants GST-Tat 1-72, GST-Tat 1-55, GST-Tat 1-45, GST-Tat 20-72, or GST-Tat 30-72 (1 or 10 nM) or with GST as a negative control for 24 h. Culture supernatants were recovered, and the presence of IL-10 was determined by ELISA. The values are the means ± SD of three experiments with cells from one donor. Similar results were obtained with cells from three different donors. (B) Tat (10 nM) was incubated for 1 h or not with MAbs directed against Tat epitopes 1 to 15, 46 to 60, or 74 to 86 (2.5 or 0.025 μg/ml) or the mixture of the three MAbs. After 24 h, culture supernatants were recovered, and the presence of IL-10 was determined by ELISA. As control, an MAb directed against gp140 of simian immunodeficiency virus was used as a control in the same conditions. Results represent the ratio of production of IL-10 by monocytes stimulated by Tat (10 nM) incubated with MAb and production of IL-10 produced after stimulation by Tat (10 nM) alone (P/P₀). On the right, the percent inhibition of IL-10 production induced by Tat (10 nM) is represented. Mouse MAbs were obtained from the Agence Nationale de la Recherche sur le SIDA (Paris, France).