The serodiagnosis of Campylobacter infection in infant cynomolgus monkeys (Macaca fascicularis) 2 to 18 weeks old by enzyme-linked immunosorbent assay

We established the enzyme-linked immunosorbent assay (ELISA) for detecting antibodies to Campylobacter and applied it in defining the period of the primary infection of Campylobacter in infant cynomolgus monkeys (Macaca fascicularis). The antibody to Campylobacter spp. could be detected with only 0.25 mul of serum by using commercially available antigens and anti-cynomolgus monkey IgG antibody conjugated with alkaline phosphatase. The inhibition experiments using extracts of C. jejuni, C. fetus and Yersinia enterocolitica demonstrated that the established ELISA system could detect species-specific anti-C. jejuni and anti-C. fetus antibodies. The levels of antibodies to both C. jejuni and C. fetus were high in 2 weeks old infant cynomolgus monkeys, rapidly decreasing until 6 to 14 weeks of age. This result indicates that the antibodies detected in 2 week old infants were IgG antibodies of maternal origin transferred through placenta. The C. jejuni was isolated from infants when the level of maternal antibody became the lowest. Infant cynomolgus monkeys obviously developed IgG antibodies to C. jejuni within 4 weeks after infection. On the other hand, no antibody response to C. jejuni was found in two infants from which it could not be isolated throughout the observation period. As regards C. fetus infection, infants showed a poor antibody response although it was more frequently isolated than C. jejuni. In conclusion, the ELISA system established in the present study is useful for the serological diagnosis of C. jejuni infection during infancy in the cynomolgus monkey.