FIG 4.

IpaB- and VirG-specific serum IgG titers correlate with reduced signs of shigellosis. IpaB- and VirG-specific IgG titers were measured in serum samples from both EcSf2a-2-vaccinated and nonvaccinated volunteers before challenge with wild-type S. flexneri 2a. IpaB- and VirG-specific IgG titers were compared with disease outcomes postchallenge: dysenteric stools (A and E), loose stools (B and F), stool volume (C and G), and temperature (D and H), using Spearman's rank correlation (r values indicated on the plots).