Antibodies to Bordetella pertussis adenylate cyclase toxin in neonatal and maternal sera

Abstract

To investigate the high prevalence among infants of antibodies to Bordetella pertussis adenylate cyclase toxin (ACT), cord-blood sera were examined for antibodies to ACT, filamentous hemagglutinin (FHA) and pertussis toxin (PT) using immunoblot analysis. Antibodies reactive with ACT were the most prevalent in neonatal sera. Similar reactivity of IgG with ACT was found in each sample of a given neonatal-maternal pair, yet IgM reactive with ACT was virtually absent in neonatal sera, suggesting that antibodies to ACT are maternally derived. Antibodies to ACT might come from infection or childhood vaccination of the mothers since pertussis vaccines from all US manufacturers elicited antibodies to ACT in mice. Alternatively, these antibodies may have been elicited by a cross-reactive antigen such as Escherichia coli alpha-hemolysin, since all of the neonatal and maternal sera contained antibodies reactive with alpha-hemolysin.

Characterization of Serological Responses to Pertussis

“…Antibody responses to ACT have been detected in healthy individuals (1,11), compromising its utility as a diagnostic antigen. The presence of antibodies in uninfected individuals could be due to cross-reactivity with other members of the RTX toxin family, including the Escherichia coli hemolysin (1,3,17,22), which lacks adenylate cyclase enzymatic activity. The 400 amino acids of the N terminus of ACT (termed CatACT) comprise the catalytic domain and are unique to ACT.…”

Adenylate cyclase toxin-hemolysin relevance for pertussis vaccines

“…Arciniega and colleagues noted in 1991 that antibodies to CyaA were common in sera from individuals diagnosed with pertussis [73]. They also found that for various B. pertussis antigens, the antibodies reactive with CyaA, presumably of maternal origin, were the most prevalent in cord-blood sera of newborns [74]. However, it remains unclear if these were due vaccination or previous infections of mothers.…”

Comparison of Western Immunobloting to an Enzyme-Linked Immunosorbent Assay for the Determination of Anti-Bordetella pertussis Antibodies

“…We found that the addition of the CatACT band did not increase the sensitivity of the immunoblot but rather significantly decreased the specificity. It has been observed that antibody responses to CatACT have been detected in healthy individuals, compromising its utility as a diagnostic antigen for pertussis infection (2). In summary, the calibration of the Viramed and Virotech immunoblots with the WHO PT standard should make these serologic tests for B. pertussis antibodies more specific.…”