How does influenza replicate in the body?
The influenza virus enters the host cell by having its hemagglutinin bind to the sialic acid found on glycoproteins or glycolipid receptors of the host. The cell then endocytoses the virus. In the acidic environment of the endosomes, the virus changes shape and fuses its envelope with the endosomal membrane.
What determines whether productive replication of the influenza virus occurs?
Cellular tropism of influenza A viruses is critically determined by the viruses’ ability to attach to and efficiently enter a specific host cell type. This process is initiated by binding of the viral HA protein to galactose (Gal)-linked sialic acid (SA) moieties of the membranous cellular cognate receptors.
Does influenza infect macrophages?
While influenza virus infection of macrophages was once thought to be abortive, it is now clear that certain virus strains can replicate productively in macrophages. This may have important consequences for the antiviral functions of macrophages, the course of disease and the outcome of infection for the host.
What cells do the influenza A virus has tropism for?
Influenza viruses primarily target airway epithelial cells via α2,3- and α2,6-type receptors, but the distribution of these receptors in many species is uncertain and may be a significant factor influencing infection.
Which cells does influenza replicate in?
Influenza viruses replicate within the nucleus of the host cell. This uncommon RNA virus trait provides influenza with the advantage of access to the nuclear machinery during replication.
Is macrophage a virus?
Both alveolar macrophages and monocyte-derived macrophages express immediate early and late gene products and they produce infectious viral particles that can be quantified in plaque assays [13,50].
How do macrophages act against viruses?
In the latter case, macrophages retard or ablate virus multiplication in neighboring cells by destroying virus-infected cells or by producing soluble factors (interferons) that act on these cells.
What are the virulence factors of influenza?
Molecules known as virulence factors are produced by bacteria, viruses, and fungi to help them to infect host cells. One of virulence factors found in the influenza A viruses is hemagglutinin (HA).
What is tropism virus?
Viral tropism can be defined by the ability of different viral strains or isolates to infect different cell types or tissues and to induce syncytia formation and/or acute or chronic infectious virus production as a result of infection.