Panel A: anti-CfaB IgG titers from the mice subcutaneously immunized with CFA/I fimbriae or CfaB major subunit recombinant protein, or the control mice; with major subunit CfaB recombinant protein as the ELISA coating antigen. Panel B: anti-CfaE IgG titers from the mice subcutaneously immunized with CFA/I fimbriae or CfaE tip subunit protein, or the control mice; with CFA/I tip subunit CfaE recombinant protein as the ELISA coating antigen. Panel C: antibody adherence inhibition against ETEC H10407 bacteria (1x103 CFUs) to Caco-2 cells from the serum samples of the mice immunized with CFA/I fimbriae, CFA/I major subunit CfaB, or CFA/I tip subunit CfaE. Antibody titers (A and B) and antibody inhibition data (C) were compared for differences between groups using One-way ANOVA with Tukey’s post hoc test and Kruskal-Wallis test with Dunn’s pairwise comparison, respectively. The line in each group represents the mean with standard deviation (A and B) or median with range (C). ** indicates a p-value of <0.01, compared the control with each immunization group.