Detection of Bordetella pertussis antibodiesin human sera by complement-fixation and immunofluorescence

Abstract

The complement-fixation test, as commonly used in the diagnosis of viral infections, was studied for its possible application to the diagnosis of whooping cough and the detection of antibody following pertussis vaccination. The results were compared with those obtained in parallel immunofluorescence tests. CFTs were performed on sera from 41 patients with whooping cough (Bordetella pertussis isolated), 125 vaccinated persons, and 618 controls; parallel tests by IF were made on sera from 24 cases of whooping cough, 36 vaccinated persons and 37 controls. Results of both tests correlated closely and showed that titres of diagnostic significance were seldom found in control sera. They also showed that, in patients suffering from whooping cough, antibody in a single specimen or a rise in antibody between paired sera was almost always demonstrated. Titres in general were lower in infants less than 6 months of age. IgG antibodies were involved in both tests. Although the number of sera tested was small both tests appear to be reliable as means of demonstrating the presence of antibody formed during the course of infection and after vaccination.

The serological diagnosis of whooping cough

“…The IHA test was more sensitive; on average it gave fourfold higher titres in vaccinated children and it was more likely to show a rise in titre in infected children. The CFT, though a less-sensitive test, detects a different antibody which does not usually persist more than 7 months after a dose of vaccine (Bradstreet et al 1972, and this study). Three of the paired sera (9, 20, 30) showed a rise in the CFT only and this makes it a useful second test for diagnosis.…”

“…The agglutination test was by the method of Preston (1970), with a formolized suspension of the 1,2,3 strain. The CFT was done by the method of Bradstreet et al (1972) with overnight fixation at 4°C but with 0-02 ml volumes in UJ-shaped Cooke's microtitre trays. All three tests were done on each serum; the starting dilution was 1/5 and the serum was inactivated at 55°C for i2 h before all three tests, though inactivation did not appear to affect the agglutination or IHA titres.…”

“…In the culture-positive cases the average gap between the first and second sera was 3-7 weeks in the nine cases where a rise in titre was shown and 2-4 weeks in the five cases where no rise was detected. Bradstreet et al (1972) found a CFT titre of > 20 in 8 out of 618 human control sera, which suggests that a titre of > 20 might be of diagnostic significance. In only two of the 14 culture-positive cases (6 and 8, Table 2) was the CFT titre > 20 in the second serum; in both these cases there was a rise in titre in all three tests.…”

“…Different CFT antigens were used in two recent studies. Bradstreet et al (1972) heated a bacterial suspension at 60 0C for 1 h and used the supernatant after centrifugation; the serotype of the strain used to make the antigen did not affect the serum titre, implying that the major antibody detected was to antigen 1 (common to all strains) or was not a type-specific antibody. The Combined Scottish Study (1970) used a recently isolated 1,3 strain and extracted their antigen with sodium hydroxide for 2 h at 37°C; they do not state if type-specific antibody was demonstrated.…”

Distribution of immunity to pertussis in the population of England and Wales

“…Subsequent workers adapted direct agglutination (Miller et al 1943;Kendrick et al 1969), indirect haemagglutination (Macaulay, 1979) and indirect fluorescence (Bradstreet et al 1972), complement fixation (Bradstreet et al 1972;PHLS, 1970) and ELISA methods (Granstrom et al 1982). Though some of these tests have proven useful as diagnostic procedures, it is unclear whether any of them is sensitive and specific as a measure of immunity to infection and there are very few data pertaining to their application in populations.…”