What do hemagglutinin and neuraminidase do?

What do hemagglutinin and neuraminidase do?

Hemagglutinin-neuraminidase allows the virus to stick to a potential host cell, and cut itself loose if necessary. Hemagglutinin-neuraminidase can be found in a variety of paramyxoviruses including mumps virus, human parainfluenza virus 3, and the avian pathogen Newcastle disease virus.

What causes antigenic drift to occur in viral infections?

Infectious Diseases Antigenic drift: A subtle change in the surface glycoprotein (either hemagglutinin or neuraminidase) caused by a point mutation or deletion in the viral gene. This results in a new strain that requires yearly reformulation of the seasonal influenza vaccine.

What is the function of hemagglutinin?

The hemagglutinin(HA) of influenza virus is a major glycoprotein and plays a crucial role in the early stage of virus infection: HA is responsible for binding of the virus to cell surface receptors, and it mediates liberation of the viral genome into the cytoplasm through membrane fusion.

What does the neuraminidase do?

The neuraminidase activity of NA protein plays a major role in the release of nascent viral particles assembled in infected cells (see Fig. 15.2). It facilitates the release of viral particles from cells by the cleavage of a sialic acid residue of glycan moiety linked to cellular glycoproteins in the plasma membrane.

What role do haemagglutinin and neuraminidase play in viral infection?

The influenza virus major surface glycoproteins, hemagglutinin (HA), and neuraminidase (NA) dominate the virion surface and form the main targets for these neutralizing antibodies. In addition to the mutations that arise due to antigenic drift, the HA and NA of influenza A viruses (IAVs) can exist in different forms.

How does neuraminidase help influenza?

Influenza A viruses generally mediate binding to cell surface sialic acid receptors via the hemagglutinin (HA) glycoprotein, with the neuraminidase (NA) glycoprotein being responsible for cleaving the receptor to allow virus release.

What is antigenic drift in influenza?

One way flu viruses change is called “antigenic drift.” Drift consists of small changes (or mutations) in the genes of influenza viruses that can lead to changes in the surface proteins of the virus, HA (hemagglutinin) and NA (neuraminidase).

What is shift and drift in influenza?

Influenza strains are constantly mutating. A small change to the genetic makeup of influenza strains is referred to as antigenic drift, while a major change is called antigenic shift.

Does coronavirus have hemagglutinin?

Human coronavirus OC43 arose relatively recently, presumably from a bovine coronavirus spillover. Both viruses use 9-O-acetylated sialoglycans as receptors to which they attach via spike protein S. Another envelope protein, hemagglutinin-esterase (HE), serves as a receptor-destroying enzyme.

How does neuraminidase work in influenza?

Drugs called neuraminidase inhibitors, which include oseltamivir (Tamiflu) and zanamivir (Relenza), inhibit the release of influenza A and B viruses from host cells. This inhibition stops the process of viral replication. Neuraminidase inhibitors are commonly used in both the prevention and the treatment of influenza.