FIG. 2.
HIV-1 infection of MDM inhibits the GM-CSF-induced phosphorylation of STAT5A on tyrosine 694. Monocytes were cultured for 5 days prior to infection with HIV-1Ba-L (+) or mock infection (−). Seven days postinfection, MDM were stimulated with 10 ng of GM-CSF per ml for the indicated times, and cells were lysed. (A) STAT5A was immunoprecipitated (IP) with an anti-STAT5A antibody (α-STAT5A), and phosphorylated STAT5A was immunoblotted (IB) with an anti-phosphorylated STAT5A/B antibody (α-phospho-STAT5A/B). (B) The ratio of phosphorylated STAT5A to the level of STAT5A was evaluated by densitometry. (C) An equivalent level of HIV-1 infection for each MDM culture was demonstrated using RT assay on culture supernatants, taken immediately prior to GM-CSF stimulation. RT activity is given as counts per minute and represents activity in 1 μl of culture supernatant. The immunoblots shown are representative of MDM prepared from seven different donors.