Campylobacter jejuni in broiler chickens: colonization and humoral immunity following oral vaccination and experimental infection.

A formalin inactivated, Campylobacter jejuni whole cell vaccine, either with or without Escherichia coli heat labile toxin (LT) as a mucosal adjuvant, was administered orally to broiler chickens. Three vaccine trials were performed, differing in the number of vaccinations, and time of administration, as well as the inclusion and dose of LT. The overall reductions of C. jejuni colonization in the vaccinated chickens ranged from 16 to 93% compared with non-vaccinated controls. Enhanced levels of anti-C. jejuni secretory IgA antibodies were demonstrated in vaccinated chickens. Vaccination also appeared to induce an anamnestic response to C. jejuni antigens in the 14-33 kDa range, as demonstrated by Western immunoblots. Interestingly, the inclusion of LT in the vaccine regimen did not appear to boost the immunogenicity of the vaccine. These results are encouraging and suggest that future development of successful oral vaccines for the control of enteropathogenic Campylobacter in poultry is feasible.