SEROLOGY OF HUMAN CAMPYLOBACTER INFECTIONS

Antibody response to campylobacter infection in man was investigated by agglutinin assay against three reference antigens and against homologous organisms isolated from patients. Sixty-six patients with diarrhoeal illness due to Campylobacter jejuni were studied. Antigens consisted of formalized cultures of motile organisms. Agglutination titres of 320 or greater were considered significant in relation to those found in a group of control subjects. At this level 77·2 per cent of sera gave significant titres against the three reference antigens and 69·6 per cent were positive against one reference antigen (strain COP). Only 31·5 per cent of 38 sera tested against one or more of the three reference strains and the corresponding homologous organism gave titres of 320 or greater against both groups, and only two sera were positive against their homologous organism and negative with all three reference strains. Because of failure to obtain sera in the first few days of illness only four of 28 paired serum samples showed four fold or greater rises in titre. IgM class antibody was detected by 2-mercaptoethanol reduction in 11 of 24 sera (46·6 per cent). Results indicated that a limited number of selected reference strains are suitable antigens for investigation of sera where culture results may be negative or where facilities for culture are inadequate. © 1979 The British Society for the Study of Infection.