What is HA and NA in influenza virus?
The influenza virus major surface glycoproteins, hemagglutinin (HA), and neuraminidase (NA) dominate the virion surface and form the main targets for these neutralizing antibodies.
What is the role of the NA protein in influenza infection?
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 are the accessory proteins of influenza?
All influenza viruses encode the polymerase subunit PB1 on segment 2; in some strains of influenza A virus, this segment also codes for the accessory protein PB1-F2, a small, 87-amino acid protein with pro-apoptotic activity, in a +1 alternate reading frame .
What are the surface proteins of the influenza virus?
Hemagglutinin (HA) and neuraminidase (NA) are the two viral surface proteins, which play important roles in the life cycle of influenza virus. Current influenza vaccines and anti-influenza drugs work mainly by interfering with the functions of the two proteins.
What is HA virus?
Hemagglutinin (HA) or Haemagglutinin (BE) is an antigenic glycoprotein found on the surface of the influenza viruses. It is responsible for binding the virus to the cell that is being infected.
What are HA and NA surface proteins?
The HA and NA surface proteins of influenza viruses are “antigens,” which means they are recognized by the immune system and are capable of triggering an immune response, including production of antibodies that can block infection.
Which virus has H and N spikes?
Influenza covers it’s shell with two types of accessories: the H spike, blue, and the N spike, red. Here the flu particle is sliced open to show its genetic material. In biology, you can’t get much simpler than viruses.
What is the function of hemagglutinin HA and neuraminidase NA )?
HA attaches virions to cells by binding to terminal sialic acid residues on glycoproteins/glycolipids to initiate the infectious cycle, while NA cleaves terminal sialic acids, releasing virions to complete the infectious cycle.
Does the influenza virus have an envelope?
The influenza virion is an enveloped virus that derives its lipid bilayer from the plasma membrane of a host cell. Two different varieties of glycoprotein spike are embedded in the envelope.
Is influenza lytic or lysogenic?
(1) The cell may lyse or be destroyed. This is usually called a lytic infection and this type of infection is seen with influenza and polio.
What is the function of the protein capsid in a virus?
Capsid proteins, designated as VP1, VP2, VP3, and VP4, are important components of infectious virions. They protect viral genomes during entry and exit from the host cells and can also modulate the activity and specificity of viral replication complexes.
What is the main function of the surface proteins on the surface of a virus?
These proteins mediate two essential functions: attachment of the virion to the cell surface; and fusion of the viral envelope with a cell membrane, resulting in accession of the viral nucleocapsid containing the genome to the cellular cytoplasm. The membrane is acquired during viral assembly within an infected cell.