Fig. 1. Systemic IgG and mucosal IgA antibody responses in BALB/c mice (n = 5) vaccinated orally with Sal-vector, Sal-optA, optB, Sal-LfliC, Sal-Lhly, or a mixture of Sal-optA, Sal-optB, Sal-LfliC, and Sal-Lhly. (A) Serum IgG obtained after vaccination with the individual vaccine strain. (B) Serum IgG obtained after vaccination with a co-mixture of all the 4 strains. (C) Intestinal sIgA obtained after vaccination with the individual vaccine strain. (D) Vaginal sIgA obtained after vaccination with a co-mixture of all the 4 strains. IgG and IgA responses measured against each LI protein by an indirect enzyme-linked immunosorbent assay using individual recombinant proteins as coating antigens.

Each data point represents mean ± standard deviation of 5 mice per group. The significance of the data was examined using the Kruskal-Wallis test with Dunn's multiple comparison test.

Ig, immunoglobulin; NS, not significant; LI, Lawsonia intracellularis; LfliC, Lawsonia flagellin; Lhly, Lawsonia hemolysin; sIgA, secretory immunoglobulin A.

^*p < 0.05.