FIG 3 .

Contribution of GAC GlcNAc side chain to GAS innate immune resistance in non-M1-serotype GAS. (a) Survival of WT (black) and ΔgacI (white) strains in isolated human neutrophils at a multiplicity of infection of 0.1; surviving CFU were quantified after 30 min (P < 0.05; indicated by an asterisk). (b) Survival in 5% baby rabbit serum; survival was quantified after a 6-h incubation at 37°C (P < 0.01; indicated by an asterisk). (c) Survival in platelet releasate; surviving CFU were quantified after 2 h (P < 0.05; indicated by an asterisk). (d) Cathelicidin human antimicrobial peptide LL-37 micromolar MICs of the WT and ΔgacI strains are displayed (t = 24 h); *, M1 data are from the work of van Sorge et al. (50). (e) Survival in whole human blood isolated from a healthy donor at the 30-min time point (P < 0.05; indicated by an asterisk). The survival of each WT strain has been normalized to 100%. Pooled normalized data from two independent experiments containing triplicate samples are shown (mean ± SEM; unpaired Student’s t test).