Effect of preincubation with fMLF on the capacity of monocytes to bind CCR5 chemokine ligand MIP-1β.

The binding of ¹²⁵I-MIP-1β to monocytes preincubated with medium or fMLF (10⁻⁶ mol/L, 37°C, 60 minutes) was measured at room temperature or at 4°C (not shown). Unlabeled MIP-1β (1 μg/mL) and fMLF (10⁻⁶ mol/L) were used to compete with ¹²⁵I-MIP-1β for binding. Aliquots of monocytes were preincubated with calphostin C (50 ng/mL, 2.5 hours at 37°C, C + fMLF) or staurosporine (1.4 ng/mL, 60 minutes, 37°C, S + fMLF) before treatment with fMLF. * Indicates significantly reduced binding of ¹²⁵I-MIP-1β on cells treated with fMLF compared with untreated cells (P < .01).