FIG. 7.

Antibody-coated polystyrene beads are avidly internalized by monocytes but do not induce cellular activation. A. Fluorescent polystyrene beads were incubated with purified human IgG and counterstained with an anti-human IgG-APC conjugate prior to flow cytometric analysis. B. Antibody-coated beads were incubated with PBMCs for 4 h and uptake by monocytes (CD14⁺ events) was assessed by flow cytometry; numbers indicate the percentage of cells containing fluorescent beads. PE, phycoerythrin. y axis, beads fluorescing in channel 1 (FITC). C. Opsonized beads do not elicit an inflammatory cytokine response. TNF-α and IL-1β in PBMC culture supernatants were measured following 8 h of incubation with the indicated stimuli. UN, unstimulated. The results shown in all panels are representative of three independent experiments.