What does filamentous hemagglutinin do?
Filamentous hemagglutinin (FHA) is a cell surface protein of Bordetella pertussis which functions as an adhesin for this organism. It is a component of many new acellular pertussis vaccines. The proposed role of FHA in immunity to pertussis is based on animal studies which have produced some conflicting results.
Is hemagglutinin an adhesin?
Abstract. Filamentous hemagglutinin (FHA) is a major adhesin produced by Bordetella pertussis, the etiologic agent of whooping cough.
Where does filamentous hemagglutinin come from?
Filamentous Hemagglutinin (FHA) FHA is a protein found on the surface of B. pertussis and secreted by the bacterium.
What is FHA in vaccines?
Additionally, clinical isolates lacking another acellular pertussis (aP) vaccine component, filamentous hemagglutinin (FHA), have been found sporadically.
What is hemagglutination reaction?
Hemagglutination is a reaction that causes clumping of red blood cells in presence of some enveloped viruses, such as the influenza virus. A glycoprotein on the viral surface, namely hemagglutinin, interacts with red blood cells, leading to the clumping of red blood cells and the formation of a lattice.
What is a function of the B pertussis rod like protein filamentous hemagglutinin FHA in pathogenicity?
Filamentous hemagglutinin (FHA) is a large (>200 kDa), rod-shaped protein expressed by bordetellae that is both surface-associated and secreted. FHA mediates bacterial adherence to epithelial cells and macrophages in vitro and is absolutely required for tracheal colonization in vivo.
What does tracheal cytotoxin do?
The tracheal cytotoxin is a cell wall peptidoglycan fragment and cannot be classified as an exotoxin or an endotoxin. The toxin kills ciliated epithelial cells in the respiratory tract and stimulates the release of interleukin 1 (IL-1), which acts as an endogenous pyrogen.
What is the structure of hemagglutinin?
Hemagglutinin consists of a globular head and a stem. The globular head consists of three chains, Chains A, C, and E. The stem of the protein consists of three chains as well, Chains B, D, and F.
Which proteins are the key virulence factors of the bacteria that cause whooping cough and cholera?
Pertussis toxin and adenylate cyclase toxin are two important virulence factors of Bordetella pertussis, the bacterial cause of the respiratory disease pertussis or whooping cough.
What makes Bordetella pertussis so virulent?
These virulence factors include adhesins such as filamentous haemagglutinin, fimbriae and pertactin, which allow B. pertussis to bind to ciliated epithelial cells in the upper respiratory tract.
What is the structure of Bordetella?
Bordetella pertussis is a small (approximately 0.8 μm by 0.4 μm), rod-shaped, coccoid, or ovoid Gram-negative bacterium that is encapsulated and does not produce spores. It is a strict aerobe. It is arranged singly or in small groups and is not easily distinguished from Haemophilus species.
Is tracheal cytotoxin a virulence factor of Bordetella pertussis?
Tracheal cytotoxin (TCT) is the only virulence factor produced by B. pertussis that has been able to recapitulate this pathology in animal models. This pathophysiology is well characterized in a hamster tracheal model, but human data are lacking due to scarcity of donor material.
Which is subunit vaccine?
Subunit vaccines are composed of protein or glycoprotein components of a pathogen that are capable of inducing a protective immune response and may be produced by conventional biochemical or recombinant DNA technologies.
What type of protein is hemagglutinin?
Structure. The hemagglutinin has a cylindrical shape and is a small protein (13 nanometers long). It’s a glycoprotein formed by three identical monomer subunits, together known as a homotrimer.
What is the role of Bordetella filamentous hemagglutinin in immunomodulation?
Bordetella filamentous hemagglutinin plays a critical role in immunomodulation, suggesting a mechanism for host specificity. P Natl Acad Sci USA. 2005; 102 :18578–83.
Which haemagglutinins are interchangeable in Bordetella pertussis (Bordetella bronchiseptica) infection?
Julio SM, Inatsuka CS, Mazar J, et al. Natural-host animal models indicate functional interchangeability between the filamentous haemagglutinins of Bordetella pertussis and Bordetella bronchiseptica and reveal a role for the mature C-terminal domain, but not the RGD motif, during infection. Mol Microbiol. 2009; 71 :1574–90.
Which fimbrial structural subunits are expressed in Bordetella bronchiseptica (Bordetella)?
Boschwitz JS, van der Heide HG, Mooi FR, et al. Bordetella bronchiseptica expresses the fimbrial structural subunit gene fimA. J Bacteriol. 1997; 179 :7882–5.
Where is the Bordetella pertussis fimbrial gene cluster located?
Willems RJ, van der Heide HG, Mooi FR. Characterization of a Bordetella pertussis fimbrial gene cluster which is located directly downstream of the filamentous haemagglutinin gene. Mol Microbiol. 1992; 6 :2661–71.