In Bangladesh and other developing countries, isolation of Campylobacter jejuni is common in healthy children, and the illness/infection ratio falls with age. To determine whether specific serum antibodies correlate with this phenomenon, using an enzyme-linked immunosorbent assay, we studied sera from 93 healthy Bangladeshi children and 121 healthy U.S. children under 15 years of age. For each age group (less than 1, 2 to 4, and 5 to 14 years) studied, specific serum antibody levels were significantly higher in the Bangladeshi children. Among Bangladeshi children, for each of the three immunoglobulin subclasses, the change in antibody levels with age was different. Specific immunoglobulin A antibody levels rose linearly with age, immunoglobulin G levels peaked in the 2- to 4-year age group and then fell, and immunoglobulin M levels peaked in the 2- to 4-year age group and then plateaued. Elevated serum antibody levels to C. jejuni in Bangladeshi children may be protective in themselves or may reflect other protective phenomena.

Blaser, M. J., Black, R. E., Duncan, D. J., & Amer, J. (1985). Campylobacter jejuni-specific serum antibodies are elevated in healthy Bangladeshi children. Journal of Clinical Microbiology, 21(2), 164–167.