Fig. 5

Intranasal immunization protected from intestinal amebiasis in a mouse model. Mice were immunized three times using an intranasal or a subcutaneous regimen with a 2-week interval between immunizations. Mice were challenged intracecally with a virulent strain of E. histolytica 4 weeks past 3rd immunization. Mice were euthanized a week after challenge and cecal contents analyzed for a antigen load using ELISA and b live amebae by culture as a measure of sterile protection. Group sample size was 13–15 mice as specified in the Materials and Methods section. Both LecA-only and adjuvant-only control groups received intranasal immunization. Antigen load in plot a was log-transformed to generate normal distributions, and one data point was identified as an outlier based on Grubb’s test (the data point is indicated by the hash mark in the plot); the statistical significance (p < 0.05) of the intranasal adjuvanted vaccine group vs. the controls was performed using Welch’s ANOVA with Games–Howell’s correction for multiple comparisons. Statistical significance was only achieved if the outlier data point was not included in the statistical analysis. Error bars represent standard error of the mean. The efficacies (e) in plot b were calculated with regard to the control groups, although statistical significance (p < 0.05) was not achieved for any group after the Bonferroni multiple comparison correction was performed