Figure 2.

Antibody response to Sda1 in mice and humans. (A–C) Mice were immunized i.n. with Mu-Sda1 or adjuvant only or infected with GAS (Materials and Methods). Two weeks after the last immunization or infection, samples of serum and mouthwash were taken for antibody determination by ELISA. Levels of mouse serum IgG (A) and IgA (B), and IgA in mouthwash (C) directed to Mu-Sda1 are shown. Data are from two to three independent experiments (n = 9–12). (D) Antigen (Ag)-specific human serum IgG responses to indicated antigens (n = 49). Data are presented as the means ± SEM from two to three independent experiments. Statistical significance was determined by one-way ANOVA with Tukey’s post-test. *** p < 0.001; **** p < 0.0001; ns, not significant. Abbreviations: CpG, CpG-oligodeoxynucleotides; KLH, keyhole limpet hemocyanin; SLO, streptolysin O; HK-GAS, heat-killed GAS.