FIG. 4.

Survival of mice intranasally immunized with the SfbI derivatives coadministered with CTB against a lethal challenge with a heterologous S. pyogenes strain. Animals (n = 10) were vaccinated and challenged with 10⁸ CFU of S. pyogenes strain NS192, following standard protocols (3), and mortality was recorded daily. The obtained results are statistically significant when compared with values for the control group (CTB alone) at P < 0.05 (∗). There is no statistically significant difference among the groups vaccinated with H2, H8, and H12.