Weak IFN-? production was detected in 1 pig from the pure culture group and 2 pigs from the mucosal homogenate group 14 d pi, and in 2 animals from both groups 20 d pi. All pigs, in both inoculated groups, were seropositive for IgG on day 20. Inoculated pigs from both groups showed very weak dose-dependent DTH reactions, which were more evident at 24 h than 48 h pi. Eight pigs from the pure culture group and 7 from the mucosa homogenate group had detectable IgA titers in the intestinal lavage 22 d pi.
In conclusion, specific local intestinal humoral and weak cell-mediated immune responses can be detected in pigs experimentally infected with L. intracellularis.
Roberto M.C. Guedes, Connie J. Gebhart. Evidence of cell-mediated immune response and specific local mucosal immunoglobulin (Ig) A production against Lawsonia intracellularis in experimentally infected swine. Canadian Journal of Veterinary. April 2010.