Fig. 4: R28 promotes adherence of S. pyogenes to human cervical epithelial cells and suppresses wound closure through a CEACAM1-dependent mechanism.

a Adherence of isogenic S. pyogenes AL368 strains to ME-180 cells at a multiplicity of infection (MOI) of 10, in the presence or absence a monoclonal antibody (mAb) specific to human CC1 and CC5 N-terminal (mean ± s.d. of n = 10 independent experiments). Statistical significance tested by one-way ANOVA with Tukey’s post-hoc test (+R28 vs. −R28 *p = 0.0142, +R28 vs. +R28 + anti-CC1/CC5 **p = 0.0071, +R28 + anti-CC1/CC5 vs. +R28 + IgG1 *p = 0.043). b, c Wound healing of ME-180 cell monolayers upon challenge with isogenic S. pyogenes AL368 strains. b Shows representative light microscopy images of ME-180 epithelia at ×10 magnification, in which the front of each scratch at 0 h is marked by a complete line and at 24 or 48 h by a dashed line. c shows the mean ± s.d. of at least n = 7 independent experiments. Statistical significance tested by one-way ANOVA with Tukey’s post-hoc test (24 h, Buffer vs. +R28 **p = 0.004, +R28 vs. −R28 ***p = 0.0002; 48 h, Buffer vs. +R28 **p = 0.0016, +R28 vs. −R28 **p = 0.0099). d Treatment of ME-180 cells with purified R28 protein suppresses wound repair (Mean ± s.d. of n = 8 independent experiments). Statistical significance tested by one-way ANOVA with Tukey’s post-hoc test (Buffer vs. R28 **p = 0.0012, R28 vs. Rib **p = 0.0056). e The impact of rR28-IgI3 protein treatment of ME-180 cell wound repair (mean ± s.d. of n = 8 independent experiments). Data generated using wildtype or mutant R28-IgI3 domains. Statistical significance tested by one-way ANOVA with Tukey’s post-hoc test (Buffer vs. WT *p = 0.0102, WT vs. Y61A **p = 0.009).