Definition: Before the structure of neuraminidase of Influenza A viruses was revealed in 1983, experiments showed that the virus produced some sort of receptor destroying enzyme, called such by researchers, RDE, until it was finally identified. Receptors can be thought of as cell docking stations. Neuraminidase destroys receptors on the newly formed viruses so they may be released from infected cells in order to seek healthy cells to infect.
Neuraminidase does not change as much as , hemagglutinin and, it also does not provoke a strong immune response, so it is not a favored antigen for the production of influenza vaccines.
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 of Influenza A are avian influenzas, bird flu. Most only occur in birds.