Kinetics of SLPI interaction with monocytes in the presence of virus. Adherent monocytes were incubated with SLPI in the presence of HIV-1Ba-L for 1 hour at 37°C. (Equivalent results were found using either 5 or 10 μg/mL SLPI; data shown were obtained with 10 μg/mL SLPI.) Cells were washed 3 times with PBS and cultured in DMEM complete medium. At designated times, supernatants were removed, cells were solubilized, and both supernatant (○) and cell lysates (•) were assayed for the presence of SLPI using a SLPI ELISA (background of assay < 100 pg/mL). The time course starts immediately after the 1-hour incubation and is indicated by the zero time point. In parallel (inset), monocytes were infected in the absence (▵) or presence of SLPI 5 μg/mL (▴) or left uninfected (▪ □) and the culture supernatants were monitored for virus by RT activity for 20 days. Values are the mean ± SD; n = 3.
