FIG. 3.
Serum levels of anti-PA IgG in mice immunized with wild-type PA or PA mutants. Each group includes eight mice immunized with three 10-μg doses of PA or mutant at 2-week intervals. Sera were obtained one week after each immunization. Boxes represent 25th to 75th percentiles of eight data points, and bars indicate minimum, median, and maximum values. After the 3rd immunization, the mean values (± standard deviation) of serum anti-PA IgG were 79.7 ± 12.8, 93.7±17.4, 100.7±17.9, 131.9±15.9, and 142.8±9.1 μg/ml in mice immunized with wild-type PA, SSSR, Rec-, Oligo-, and DNI, respectively. The pairwise p values (mutant vs. PA) are 0.53, 0.36, 0.023*, and 0.0013* for SSSR, Rec-, Oligo-, and DNI, respectively (* denotes statistically significant [p < 0.05]).