Detection of serum antibody response in patients infected with one strain of Campylobacter jejuni with a DIG-ELISA method.

Paired sera from 10 patients and a convalescence sample from one patient suffering from campylobacteriosis were analysed for IgG, IgM and IgA antibodies against the infective organism (Campylobacter jejuni PEN 0:6,7) with a DIG-ELISA system. Either formalinized, ethanol-inactivated or heat-inactivated preparations of the infecting organism were used as antigens. Cross reactivity was tested with human sera having agglutinating antibodies against Yersinia enterocolitica (N = 6) or Salmonella typhi or S. parathyphi b (N = 7). All patients displayed IgA and IgM levels in the convalescence sample above that found in healthy blood donors (N = 55). Using the ethanol-inactivated or formalinized preparations more than 90% of the convalenscence sera showed IgG levels above that found in blood donors whereas the heat-inactivated preparation detected 73% IgG positives in the same group of sera. Serum from one patient infected with S. parathyphi b was positive in the test. This finding was interpreted as most likely due to a double infection. The study suggests that serum IgA may be a valuable marker for infection with this microorganism. Both the formalinized and the ethanol-inactivated preparations showed presence of flagella in contrast to the heat-inactivated preparation.