Hemagglutinin is an important factor in the virulence of Influenza A and it gets its name because it is responsible for agglutinating red blood cells, that is, sticking them together. It also is the culprit for the virus’s ability to bind to cells. It wasn’t until 1981 that scientists got a real close picture of hemagglutinin and the structure of the protein helped scientist decipher how it works in making a virus severe, or not.
The H and the N are both antigens, what provokes the immune system of the body to defend itself. These antigens, both proteins called glycoproteins, are found on the surface of the knobbly sphere-like Influenza A virus.
H5N1 is just one of many subtypes of the Influenza A viruses. There are 15 different “H” proteins and 9 different “N” proteins creating different combinations between them. All of the HXNY (where X and Y are numbers) subtypes are avian influenzas, bird flu. Most only occur in birds.
The body creates a better immune response to hemagglutinin than to neuraminidase, but it is the hemagglutinin that changes quickly from one variation to another. Always wearing another hat, it is difficult to [http://birdflu.about.com/od/vaccine/a/panfluvacc.htm]create a vaccine[/link] to a hemagglutinin today that could look a bit different tomorrow and render the vaccine ineffective.
- Center for Infectious Disease Research and Policy, CIDRAP. Avian Influenza (Bird Flu): Implications for Human Disease. Updated July 19, 2006.
- Viruses, From Structure to Biology. Washington University Department of Molecular Microbiology. The Influenza Virus Hemaggluntinin. http://medschool.wustl.edu/~virology/influenza.htm