FIG. 6.

Capsule reduces opsonophagocytosis of B. pseudomallei by PMNL. Bacteria labeled with [¹⁴C]lysine were incubated with human PMNL in the presence of 10 or 30% NHS and subjected to differential centrifugation. Samples were counted in a Beckman LS 6500 scintillation counter, and the percentage of the bacterial population phagocytosed was calculated by the following equation: percent uptake = [counts per minute following differential centrifugation (cell associated)/counts per minute in noncentrifuged tubes (cell and non-cell associated)] × 100. The data represent the means and the standard deviations from three separate experiments, each performed in triplicate. The difference in opsonophagocytosis between B. pseudomallei 1026b and SR1015 was determined to be significant at both 10% NHS (P < 0.001) and 30% NHS (P < 0.001).