نتایج جستجو برای: antigenic drift
تعداد نتایج: 50696 فیلتر نتایج به سال:
The threat of influenza A and B variants via antigenic drift and emerging novel influenza A and B strains in the human population via antigenic shift has spurred research efforts to improve upon current seasonal influenza vaccines. In recent years, a wave of novel technological breakthroughs has lead to the identification of many broadly anti-influenza hemagglutinin (HA) monoclonal antibodies (...
The 2010 Cochrane review on efficacy, effectiveness and safety of influenza vaccination in the elderly by Jefferson et al. covering dozens of clinical studies over a period of four decades, confirmed vaccine safety, but found no convincing evidence for vaccine effectiveness (VE) against disease thus challenging the ongoing efforts to vaccinate the elderly. However, the Cochrane review analyzed ...
The neutralization titer of a hemagglutinin (HA)-specific neutralizing antibody against new isolates reflect both the antigenic drift and the conformation status of HA protein in these new influenza viruses. Since most antigenic sites are in the HA1 domain of HA, using HA1 domain of influenza virus as antigen is of great importance in vaccine development. In this study, we investigate different...
The accumulation of cross-immunity in the host population is an important factor driving the antigenic evolution of viruses such as influenza A. Mathematical models have shown that the strength of temporary non-specific cross-immunity and the basic reproductive number are both key determinants for evolutionary branching of the antigenic phenotype. Here we develop deterministic and stochastic ve...
Human infection with avian influenza A(H9N2) virus was identified in Bangladesh in 2011. Surveillance for influenza viruses in apparently healthy poultry in live-bird markets in Bangladesh during 2008-2011 showed that subtype H9N2 viruses are isolated year-round, whereas highly pathogenic subtype H5N1 viruses are co-isolated with subtype H9N2 primarily during the winter months. Phylogenetic ana...
History suggests that the 2009 pandemic H1N1 influenza virus faces extinction unless it mutates to avoid already high global population immunity. The immune escape mechanisms potentially at its disposal include antigenic drift, antigenic shift via genetic reassortment, and intrasubtypic reassortment. Going back to the late 19th century, the evolutionary histories of past pandemic viruses are ex...
Current vaccine strategies against influenza focus on generating robust antibody responses. Because of the high degree of antigenic drift among circulating influenza strains over the course of a year, vaccine strains must be reformulated specifically for each influenza season. The time delay from isolating the pandemic strain to large-scale vaccine production would be detrimental in a pandemic ...
Effective annual influenza vaccination requires frequent changes in vaccine composition due to both antigenic shift for different subtype hemagglutinins (HAs) and antigenic drift in a particular HA. Here we present a broadly neutralizing human monoclonal antibody with an unusual binding modality. The antibody, designated CT149, was isolated from convalescent patients infected with pandemic H1N1...
A panel of 6 neutralizing monoclonal antibodies (MAbs) raised against A/Moscow/IIV01/2009 (H1N1) virus isolated during the 2009 pandemic was used for the selection of 26 escape mutants. The mutants were characterized in immune cross-reactions with the panel of MAbs. The sequencing of the mutant HA genes revealed 5 amino acid positions recognized by monoclonal antibodies: 129, 156, 158, 159, and...
The number of N-linked glycosylation sites in the globular head of hemagglutinin (HA) has increased during evolution of H3N2 human influenza A virus. Here natural selection operating on the gains of N-linked glycosylation sites was examined by using the single-site analysis and the single-substitution analysis. In the single-site analysis, positive selection was not inferred at the amino acid s...
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