Filamentous Hemeagglutinin, B. pertussis (FHA)

Molecular Biology / MB-Infectious Disease

-20°C

Supplied as a liquid in PBS, pH 8, 1.25% trehalose.

Bordetella pertussis is a Gram-negative, aerobic coccobacillus of the genus Bordetella, and the causative agent of pertussis or whooping cough. Unlike B. bronchiseptica, B. pertussis is non-motile. There does not appear to be a zoonotic reservoir for B. pertussis— humans are its only host. The bacterium is spread by coughing and by nasal dripping. The incubation period is 7-14 days. Pertussis (or whooping cough) is an infection of the respiratory system and characterized by a “whooping” sound when the person breathes in. In the US it killed 5, 000 to 10, 000 people per year before a vaccine was available. Worldwide in 2000, according to the WHO, around 39 million people were infected annually and about 297, 000 died. Bordetella pertussis infects its host by colonizing lung epithelial cells. The bacterium contains a surface protein, filamentous hemagglutinin (FHA), which binds to sulfatides that are found on cilia of epithelial cells. Once anchored, the bacterium produces tracheal cytotoxin, which stops the cilia from beating. This prevents the cilia from clearing debris from the lungs, so the body responds by sending the host into a coughing fit. These coughs expel some bacteria into the air, which are free to infect other hosts.

Filamentous hemagglutinin (fimbrial hemagglutinin or FHA) is one of two hemagglutinins produced by phase I strains of Bordetella pertussis. The use of FHA as one component of a new acellular vaccine is currently under investigation. FHA is named for its rod-like shape and its ability to agglutinate erythrocytes from a variety of species. On a weight basis, FHA is five to seven times more active in hemagglutination (HA)assays than is pertussis toxin. Moreover, the HA-activity of FHA, but not that of pertussis toxin, is abolished in the presence of low levels of cholesterol. FHA is a protein with an approximate molecular weight of 200, 000 daltons. However, some preparations of this protein contain varying amounts of two lower molecular weight components in the 90, 000 to 130, 000 dalton range. Although monoclonal and polyclonal antibodies prepared against FHA also react with these faster migrating components, it is not known whether the latter represent degradation products or subunits of FHA.
Pertussis vaccine is part of the DTaP (diphtheria, tetanus, acellular pertussis) immunization. Acellular pertussis vaccines contain antigen components of B. pertussis, usually lymphocytosis promoting factor (LPF) which is also called pertussis-toxin (PT) or pertussigen, filamentous hemagglutinin (FH) and, eventually, agglutinogens 2 and 3.

Source:
FHA, from Bordetella pertussis

Storage and Stability:
May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.