FIG. 1.

In vitro bactericidal tests performed with rabbit antisera against the 26-valent M protein-based group A streptococcal vaccine and subtypes of M1 (A), M3 (B), and M5 (C). Percent kill (±standard error of the mean) was calculated based on the formula provided in Materials and Methods. The number within the base of each bar indicates the number of assays performed for each strain. *, statistically significant difference (P < 0.001) compared to the result obtained with M1.0 based on a one-way analysis of variance.