HIV-1 gp120, MAC-PPD, and LPS induce release of sCD14 from monocytes. Freshly isolated monocytes from healthy donors release sCD14 after 72 hours of stimulation with viral and bacterial components. (A) Recombinant HIV-1 gp120 induces release of sCD14 from monocytes in a dose-dependent manner. (B) MAC-PPD (◊) stimulated monocytes to release sCD14, although not as potently as LPS (+). 0 means unstimulated cells. The mean of duplicates is shown; data are from one experiment representative of three performed.