How is sialic acid related to influenza?

Influenza viruses bind to sialic acid (SA) residues that are bound to glycans through α2,3 or α2,6 linkage on the host cells14. The expression of the appropriate host cell receptor to which viral haemagglutinin (HA) can bind is the key determinant of the ability of IAVs to infect a host15.

What cells have sialic acid receptor?

Alpha(2,3) linked sialic acids are found on ciliated epithelial cells, which are a minor population within the human respiratory tract, and also on some epithelial cells in the lower tract. This receptor specificity has implications for human infection with avian influenza virus strains.

What is the host receptor for the influenza A virus?

The host receptors that influenza viruses bind to contain the three common terminal saccharides SA1, galactose (Gal2) and N-acetylglucosamine (GlcNAc3)22 (the numbers correspond to the position of the terminal saccharides), and the penultimate Gal is linked to either α2,3-SA or α2,6-SA.

What is the function of sialic acid in cells?

Sialic acids (Sias) are nine-carbon atoms sugars usually present as terminal residues of glycoproteins and glycolipids on the cell surface or secreted. They have important roles in cellular communication and also in infection and survival of pathogens.

Which sugar does influenza bind to?

You can see the individual ‘spikes’ on the virion binding to a structure on the cell. The influenza viral spike that attaches to the cell receptor is the HA protein – hemagglutinin. The cell receptor is sialic acid – a small sugar that is attached to many different proteins on the cell surface.

What binds to sialic acid?

The trimeric viral haemagglutinin protein binds to sialic acid, commonly Neu5Ac, to adhere to host cells. Influenza viruses engage α2,3-linked and α2,6-linked sialic acid attached to a penultimate galactose of the glycan receptor.

What receptors does influenza bind to?

The cell entry of influenza virus is governed by receptor biology. Sialic acids (SAs) of cell surface glycoproteins and glycolipids are the receptors for the influenza virus, recognized by the viral glycoprotein hemagglutinin (HA; Figure 1).

Is influenza A natural virus?

Influenza is an infectious respiratory disease that, in humans, is caused by influenza A and influenza B viruses. Typically characterized by annual seasonal epidemics, sporadic pandemic outbreaks involve influenza A virus strains of zoonotic origin.

Is influenza A virus?

There are two main types of influenza (flu) virus: Types A and B. The influenza A and B viruses that routinely spread in people (human influenza viruses) are responsible for seasonal flu epidemics each year. Influenza A viruses can be broken down into sub-types depending on the genes that make up the surface proteins.

Why is sialic acid bad for you?

Function. Sialic acid containing glycoproteins (sialoglycoproteins) bind selectin in humans and other organisms. Metastatic cancer cells often express a high density of sialic acid-rich glycoproteins. This overexpression of sialic acid on surfaces creates a negative charge on cell membranes.

What foods are high in sialic acid?

Dietary sources that are rich in Neu5Gc include red meats such as beef, pork, lamb, and to a much lesser degree, cow’s milk products. Of significant note is the fact that plants and poultry do not contain Neu5Gc, and that fish samples studied so far contain low to trace amounts (58, 60).

What human cells does influenza infect?

1. Influenza virus directly infects primary human NK cells.

How are sialic acid receptors and influenza virus different?

Distribution of sialic acid receptors and influenza A virus of avian and swine origin in experimentally infected pigs A difference in predilection sites between SIV and AIV virus was found, and this difference was in accordance with the distribution of the SA-alpha-2,6 and SA-alpha-2,3 receptor, respectively.

What is the role of sialic acid receptors?

Sialic acid receptors: focus on their role in influenza infection. Abstract: Receptor-binding specificity is a major determinant of host range, pathogenesis, and interspecies transmission in influenza virus.

Where are the receptors for the influenza virus?

The cell entry of influenza virus is governed by receptor biology. Sialic acids (SAs) of cell surface glycoproteins and glycolipids are the receptors for the influenza virus, recognized by the viral glycoprotein hemagglutinin (HA; Figure 1). The site on HA at which the cellular receptors are bound is at the distal end of the molecule.

How is the attachment of sialic acid mediated?

Attachment to sialic acid is mediated by receptor binding proteins that are constituents of viral envelopes or exposed at the surface of non-enveloped viruses. Some of these viruses are also equipped with a neuraminidase or a sialyl-O-acetyl-esterase.