Figure 4. Effect of inhibiting complement, CD14, and a combination thereof, on E. coli-induced cytokine release.

Upper panels: Pig whole blood was preincubated with 0.64 μM OmCI (O), 25 μg/ml anti-CD14 (whole IgG) (α), and the combination of both and then incubated with 10⁶ E. coli/ml for 2 h (TNF-α and IL-8) and/or 10⁵ bacteria/ml for 4 h (IL-1β and IL-8). The effect of anti-CD14 on pig IL-8 could not be measured because of assay intereference. Albumin and an isotype-matched control Ab (IgG2b) were used as controls (Ctr) when analyzing TNF-α and IL-1β, whereas albumin only was used as control when analyzing IL-8. For IL-8, 2 and 4 hour sample data were pooled. Data are normalized to the E. coli group which is defined as 100%. Data are presented as mean ± SEM (n = 3, 4 and 5 for TNF-α, IL-1β and IL-8, respectively).

Lower panels: Human whole blood was preincubated with 0.64 μM OmCI, 10 μg/mL anti-CD14 (F(ab′)₂), combinations thereof, and controls for 5 minutes and then incubated for 2 h with 10⁶ E. coli/ml at 37 °C. As control (Ctr) albumin was used in combination with a control F(ab′)₂, both in equimolar amounts to OmCI and anti-CD14, respectively. Data are normalized to the E. coli group which is defined as 100% and presented as mean ± SEM (n=3). Statistical comparisons were performed between the effect of OmCI, anti-CD14 and the combinations of both versus no inhibition, *p < 0.05.