Filamentous hemagglutinin of Bordetella pertussis (FHA)

Filamentous hemagglutinin is a large (~220–250 kDa) extracellular glycoprotein adhesin, encoded by the fhaB gene, that is surface-associated on Bordetella pertussis and released into the extracellular environment during infection. FHA is secreted via the two-partner secretion (TPS/Type Vb) pathway, which requires its transporter FhaC. Its primary role is to mediate tight adherence of the bacterium to ciliated respiratory epithelial cells, facilitating colonization, immune evasion, and the persistence of infection. FHA suppresses inflammatory responses and enables Bordetella pertussis to persist in the host. The protein contains specialized domains, such as the heparin-binding domain (HBD) near the N-terminus, facilitating interactions with host cell surface carbohydrates. FHA's importance as a vaccine antigen makes it a critical biotherapeutic target in the prevention and control of whooping cough. It also interacts with other Bordetella virulence factors, notably adenylate cyclase toxin (ACT), with which it can form surface associations that contribute to immune suppression and enhance bacterial survival.

Other names

FHAFilamentous hemagglutininFhaB

Vaccines: Acellular vaccines stimulate the immune system to develop neutralizing antibodies against FHA, blocking adherence and colonization or promoting clearance. Not a direct pharmacological target for small molecules