FIG. 4.

Killing of Y1C12 occurs via an IgG-dependent classical pathway. (A) Total CFU present after incubation of wt or Y1C12 C. canimorsus in 10% HI NHS (black), NHS (dark gray), Ab-depleted NHS (light gray), or Ab-depleted NHS supplemented with HI NHS as a source of Abs (white) for 180 min at 37°C. (B) Total CFU present after incubation of wt or Y1C12 C. canimorsus in 10% HI NHS (black), NHS (gray), or Mg-EGTA-treated NHS (white) for 180 min at 37°C. (C) Binding of human serum Abs to wt, Y1C12, or cY1C12 C. canimorsus after 30 min incubation with HI NHS. The level of Ab deposition on bacteria was quantified by FACS analysis using anti-human IgG-FITC Ab. Results are the means of at least three independent experiments ± standard deviations (bars).