Figure 4. Fibrinogen is required for M1 protein-induced HBP release by purified neutrophils.
Fibrinogen (150 µg), M1 protein (0.5 µg), or fibrinogen (150 µg) plus M1 protein (0.5 µg) were dissolved in 0.45 ml PBS, followed by the addition of 50 µl responder (filled bars) or non-responder serum (open bars). Neutrophils (2×105 cells) were added and after incubation for 30 min at 37°C, cells were spun down and the amount of HBP was determined in the supernatants. The figure shows the mean±SD of three separate experiments. The data obtained with responder serum were compared using one way analysis of variance, and the results showed a statistically significant difference (p<0.001). The results obtained with M1 protein+fibrinogen were compared with the HBP release generated by buffer, fibrinogen or M1 protein alone, using the Bonferroni corrected t-test. The corresponding p-values are indicated.