FIG. 2.

Cc5 cells are resistant to PMN-mediated killing. Levels of phagocytosis and killing were determined 120 min after infection of human PMNs. PMNs were infected with either Cc5 or wt Y. enterocolitica at an MOI of 1. Infection with nonopsonized (black), HI NHS-opsonized (gray), or C7-depleted NHS-opsonized bacteria (white) are shown. Results are the means of at least three independent experiments ± standard deviations (bars). The statistical significance of the difference between Cc5 and wt Y. enterocolitica (unopsonized) is given, with * indicating a P value of <0.05 and ** indicating a P value of <0.01, using a two-tailed unpaired Student's t test.