8/14/2023 0 Comments Antigenic shift covid 19Sera from individuals with narrowly focused influenza virus antibodies rapidly select viral escape mutations in ovo. Some of these mutations render antibodies elicited against earlier virus strains less effective. Recent SARS-CoV-2 variants contain changes, or mutations, at a key site on the spike protein called the receptor-binding site (RBS). Defining influenza A virus hemagglutinin antigenic drift by sequential monoclonal antibody selection. SARS-CoV-2, the virus that causes COVID-19, uses a protein called the spike protein to recognize and enter host cells. Fitness costs limit influenza A virus hemagglutinin glycosylation as an immune evasion strategy. Defining B cell immunodominance to viruses. 2019 10:e00204-19.Īngeletti D., Gibbs J.S., Angel M., Kosik I., Hickman H.D., Frank G.M., Das S.R., Wheatley A.K., Prabhakaran M., Leggat D.J., et al. Human Influenza A Virus Hemagglutinin Glycan Evolution Follows a Temporal Pattern to a Glycan Limit. Note that in the Figure, the yellow mutant is less fit in non-immune host (losing the competition to the other mutants) but much more fit when Ab neutralization is added to the various selection factors.Īltman M.O., Angel M., Košík I., Trovão N.S., Zost S.J., Gibbs J.S., Casalino L., Amaro R.E., Hensley S.E., Nelson M.I., Yewdell J.W. In the latter case, this will be a very infrequent event because so few viruses are transmitted, but given enough transmission events to immune individuals, it can contribute to antigenic drift. Ab selection can occur either in the transmitting host or the recipient host. Some antigenic determinants from HA and NP of influenza virus A were also in antigenic sites of SARS-CoV-2 and these antigens from influenza virus have role in assembly of newly budded virions in case of influenza virus A. In the presence of neutralizing Abs, viruses with mutations that enable escape from neutralization are rapidly selected, resulting in antigenic drift. This results in the steady accumulation of mutants as a virus circulates. Genetic versus antigenic drift Nearly every virus generated in a host (depicted as a metaphorical bottle) possesses at least one point mutation. Transmission of a very limited number of viruses between hosts (bottlenecking, 5 different mutants in the figures) results in the random selection of mutants that compete in the new host (generating a hierarchy as shown, with the blue virus becoming extinct with the purple virus at the top), all the while generating a new repertoire of mutants that are bottlenecked in transmitting to the next host.
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