FIG. 1.
Bactericidal activity of neutrophil secretions in a radial diffusion assay. Five microliters of neutrophil secretion (equivalent to that from 5 × 105 neutrophils) was added into each well. Secretions were obtained from unstimulated neutrophils (N), neutrophils stimulated with PMA (100 ng/ml) for 30 min in the absence of CMK, with CMK added to the secretion after neutrophils were removed [(N+P)+C], or neutrophils stimulated with PMA in the presence of CMK (N+C+P). Zones of clearance were measured with a calibrated microscope. The microbicidal activity was expressed in arbitrary units (0.1 mm = 1 U) by subtracting the diameter of the well (3 mm) from the diameter of the clear zone. Open bars, E. coli; solid bars, L. monocytogenes. Data are means ± standard deviations from assays performed twice in duplicate.