Pertussis toxin and related Bordetella pertussis antigens (PT/FHA/PRN/FIM)

Pertussis toxin (PT) and related antigens, including filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae (FIM), are the primary virulence factors of Bordetella pertussis, the causative agent of whooping cough (StatPearls, 2023). PT is a complex AB5-type exotoxin that enters host cells and ADP-ribosylates the alpha subunit of inhibitory G proteins (Gi), leading to disrupted cAMP signaling and impaired immune cell recruitment (UniProt, 2024). FHA, PRN, and FIM function as adhesins, enabling the bacteria to colonize the ciliated respiratory epithelium and resist mechanical clearance (PubMed, 2021). These antigens serve as the essential components of modern acellular pertussis vaccines, such as DTaP and Tdap, which are designed to stimulate a protective humoral immune response (FDA, 2023). By targeting these proteins, vaccines prevent both the systemic toxic effects of PT and the localized colonization of the respiratory tract. However, the emergence of pertactin-deficient strains and the relatively rapid waning of acellular vaccine-induced immunity remain significant challenges in public health (CDC, 2022).

Other names

PTXPTFilamentous hemagglutininFHAPertactinPRNFimbriae types 2 and 3FIM2/3Bordetella pertussis virulence factors

Active immunization via these antigens induces the production of neutralizing antibodies that block toxin activity and prevent bacterial adherence to respiratory epithelial cells (CDC, 2022).