Figure 1. Effect of various human commensals on PLP_91–110-induced EAE in HLA-DR3.DQ8 transgenic mice.

Animals were immunized with PLP_91–110 peptide and treated with either bacteria or medium starting at day 7 post-immunization and every other day for a total of 7 doses. A) Only P. histicola treated mice had late disease onset and lower disease incidence. No significant effect was observed in the groups receiving P. melaninogenica, C. sputigena, or E. coli. Animals were scored daily for disease, and the daily mean disease score for each group is plotted. Error bars represent the standard error of mean. B) P. histicola treated animals had a lower average cumulative disease score compared with medium treated animals. The data in figures A and B represent average cumulative scores of 3 experiments performed at different times with n=10 mice per group. C) Mice were sacrificed on day 30 post-immunization and the brain and spinal cord were examined by histopathology. Representative photomicrographs show mild to severe inflammation and demyelination in medium treated mice compared with P. histicola treated mice. D) Quantitative analysis of spinal cord pathology similarly showed increased inflammation and demyelination in medium treated groups compared with the P. histicola treated group. The data in figures C and D represent 1 of 3 experiments performed at different time points (n=5 mice per group). A single asterisk indicates p≤0.05, double asterisks indicate p≤0.005, and ‘n.s.’ indicates not significant, when compared to medium treated group.