Related Experiment Videos
Evolutionary pattern of human respiratory syncytial virus (subgroup A): cocirculating lineages and correlation of
1Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
Abstract:
The genetic and antigenic variability of the G glycoproteins from 76 human respiratory syncytial (RS) viruses (subgroup A) isolated during six consecutive epidemics in either Montevideo, Uruguay, or Madrid, Spain, have been analyzed. Genetic diversity was evaluated for all viruses by the RNase A mismatch cleavage method and for selected strains by dideoxy sequencing. The sequences reported here were added to those published for six isolates from Birmingham, United Kingdom, and for two reference strains (A2 and Long), to derive a phylogenetic tree of subgroup A viruses that contained two main branches and several subbranches. During the same epidemic, viruses from different branches were isolated. In addition, closely related viruses were isolated in distant places and in different years. These results illustrate the capacity of the virus to spread worldwide, influencing its mode of evolution. The antigenic analysis of all isolates was carried out with a panel of anti-G monoclonal antibodies that recognized strain-specific (or variable) epitopes. A close correlation between genetic relatedness and antigenic relatedness in the G protein was observed. These results, together with an accumulation of amino acid changes in a major antigenic area of the G glycoprotein, suggest that immune selection may be a factor influencing the generation of RS virus diversity. The pattern of RS virus evolution is thus similar to that described for influenza type B viruses, expect that the level of genetic divergence among the G glycoproteins of RS virus isolates is the highest reported for an RNA virus gene product.
Insights
Genetic and antigenic analysis of human respiratory syncytial virus (RSV) G glycoproteins reveals significant diversity. Immune selection appears to drive RSV evolution, similar to influenza B, but with higher genetic divergence in the G glycoprotein.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Human respiratory syncytial virus (RSV) is a major cause of respiratory illness.
- The G glycoprotein is a key determinant of RSV host immunity and viral diversity.
- Understanding RSV genetic and antigenic variability is crucial for developing effective vaccines and therapeutics.
Purpose of the Study:
- To analyze the genetic and antigenic variability of the G glycoproteins from human respiratory syncytial virus (RSV) subgroup A.
- To investigate the evolutionary patterns and potential drivers of RSV diversity.
Main Methods:
- Genetic diversity analysis using RNase A mismatch cleavage and dideoxy sequencing.
- Phylogenetic analysis of G glycoprotein sequences.
- Antigenic analysis using a panel of anti-G monoclonal antibodies.
Main Results:
- RSV subgroup A G glycoproteins exhibit significant genetic and antigenic variability.
- Phylogenetic analysis revealed two main branches and several subbranches within subgroup A viruses.
- A strong correlation was observed between genetic relatedness and antigenic relatedness of the G protein.
- Accumulation of amino acid changes in a major antigenic site suggests immune selection pressure.
Conclusions:
- The G glycoprotein's high genetic divergence and antigenic variability suggest a rapid evolutionary rate for RSV.
- Immune selection is a significant factor influencing the generation of RSV diversity.
- RSV evolution shares similarities with influenza B virus, but with a higher level of genetic divergence in the G glycoprotein.