FIG 2.

Complement titrations. Shown is the survival of S. Typhimurium D65 (A), S. Enteritidis R11 (B), S. Typhi Ty2 (C), all grown to log phase (OD₆₀₀, 0.4), and S. Paratyphi A ATCC 9150 (D) grown to stationary phase with BRC in the presence of immune (I) compared to nonimmune (NI) sera and decreasing complement concentrations. The results are shown as the mean ± standard deviation values from more than three independent experiments. *, P < 0.05, and **, P < 0.01, by Student's t test (two-tailed). The dashed lines represent 100% of inoculum as a visual reference.