antigenic shift


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Related to antigenic shift: Antigenic drift

antigenic shift

[‚an·tə¦jen·ik ′shift]
(virology)
An abrupt major change in the antigenicity of a virus; believed to result from recombination of genes.
References in periodicals archive ?
Type A is likely to undergo an antigenic shift if two or more subtypes infect a single host, creating new subtypes based on surface antigens hemagglutinin (H) and neuraminidase (N).
Antigenic shift involves the replacement of entire gene segments within influenza A viruses and results in novel viruses.
Here's where the antigenic shift comes in: If chromosomes from the two viruses recombine within infected cells in just the right formula, they can spawn a new virus with antigens that the human body may not recognize.
This form of influenza tends to undergo both the antigenic drift as well as the antigenic shift.
Antigenic shift leads to replacement of circulating strains with new variants that are able to reinfect hosts immune to earlier types; the result is usually a pandemic.
As populations have no immunity to the new subtype, and as no existing vaccines can confer protection, antigenic shift has historically resulted in highly lethal pandemics.
The predominant H3N2 variant has been "uncharacteristically" stable over the last few years and a significant antigenic shift is anticipated, Dr.
As populations will have no immunity to the new subtype, and as no existing vaccines can confer protection, antigenic shift has historically resulted in highly lethal pandemics.
Governments are now preparing contingency plans against the effects of an expected further antigenic shift.