Utility of lipopolysaccharides from Bordetella pertussis and Bordetella parapertussis in the serodiagnosis of pertussis and parapertussis

Abstract

Bordetella pertussis (Bp) and Bordetella parapertussis (Bpp), which are responsible for outbreaks of whooping cough in humans, are closely related, and it is difficult to discriminate between these species immunologically. We developed an immunodiagnostic method using an enzyme-linked immunosorbent assay (ELISA) or immunoblotting, on the basis of the serological differences between lipopolysaccharide (LPS) from Bp and Bpp. In ELISA, the sera from nine out of 11 patients with pertussis (about 80%) possessed high reactivities against whole cells (WC) of Bp in comparison with Bpp-WC, whereas the sera from five patients with the same disease (about 45%) reacted with Bp-LPS more than with Bpp-LPS. High reactivity against Bpp-WC and Bpp-LPS in the sera from 13 out of 16 patients with parapertussis (about 80%) was shown as compared with that against Bp-WC and Bp-LPS, respectively. Immunoblotting showed that all of the sera from pertussis patients reacted more strongly with Bp-LPS than with Bpp-LPS, except those which were unreactive. Almost all of the sera from parapertussis patients reacted with Bpp-LPS more than with Bp-LPS. These results indicated that immunoblotting, rather than ELISA, using LPS from Bp and Bpp is useful for serodiagnosis to distinguish between pertussis and parapertussis.