What do you mean by antigenic drift?
antigenic drift, random genetic mutation of an infectious agent resulting in minor changes in proteins called antigens, which stimulate the production of antibodies by the immune systems of humans and animals. These mutations typically produce antigens to which only part of a population may be immune.
What causes antigenic drift?
20 Antigenic drift is caused by point mutations in the HA and NA genes that are driven by immune pressure and the infidelity inherent in the replication of RNA genomes.
What is the difference between antigenic shift and antigenic drift?
Antigenic drift involves the accumulation of a series of minor genetic mutations. Antigenic shift involves “mixing” of genes from influenza viruses from different species. Pigs, birds, and humans.
Where does antigenic drift occur?
Antigenic drift is a natural process whereby mutations (mistakes) occur during replication in the genes encoding antigens that produce alterations in the way they appear to the immune system (antigenic changes) (Figure 1).
What causes antigenic shift and drift?
Antigenic Shift This shift typically occurs when a human flu virus crosses with a flu virus that usually affects animals (such as birds or pigs). When the viruses mutate, they shift to create a new subtype that is different from any seen in humans before. A human flu virus infects an animal, such as a pig.
What does 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.
Which viruses have antigenic drift?
Antigenic drift occurs in both influenza A and influenza B viruses. (Confusion can arise with two very similar terms, antigenic shift and genetic drift. Antigenic shift is a closely related process; it refers to more dramatic changes in the virus’s surface proteins.
Does pandemic cause antigenic drift?
For more information, see pandemic flu. Type A viruses undergo both antigenic drift and shift and are the only flu viruses known to cause pandemics, while flu type B viruses change only by the more gradual process of antigenic drift.
Does antigenic drift occur in all viruses?
All influenza viruses experience some form of antigenic drift, but it is most pronounced in the influenza A virus. Antigenic drift should not be confused with antigenic shift, which refers to reassortment of the virus’ gene segments.
What is the best example of an antigenic shift?
An example of a pandemic resulting from antigenic shift was the 1918-19 outbreak of Spanish Influenza. This strain was originally the H1N1 avian flu, however antigenic shift allowed the viral infection to jump from pigs to humans, resulting in a large pandemic which killed over 40 million people.
What is the purpose 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.
https://www.youtube.com/watch?v=tMTl3gU0mFc