Final answer:
The two coat proteins of influenza A virus are hemagglutinin (H) and neuraminidase (N), which are critical for viral entry and exit from host cells. These proteins serve as the basis for the classification of influenza strains and are targets for flu vaccines.
Step-by-step explanation:
The two coat proteins of influenza A are hemagglutinin (H) and neuraminidase (N). These proteins are crucial for the virus's ability to infect host cells and are the basis for the classification of different strains, like H1N1 and H3N2. The hemagglutinin protein facilitates the binding of the virus to sialic acid receptors on the surface of host respiratory epithelial cells, leading to endocytosis and entry of the viral particle into the cell.
On the other hand, neuraminidase assists in the release of newly formed virions from the host cell by cleaving sialic acid receptors, ensuring that progeny viruses can exit successfully when budding from an infected cell.The importance of the H and N proteins is not limited to their biological functions; they also have clinical significance.
The annual formulation of flu vaccines often includes variants of these proteins to elicit an immune response that will protect against the most prevalent and virulent influenza strains in a given year. Knowledge of these proteins is vital for both understanding the pathogenesis of influenza and the development of strategies for prevention and treatment.