Application of gene sequence cluster in research for H3 antigenic evolution of influenza A virus / 中华流行病学杂志

ABSTRACT

<p><b>OBJECTIVE</b>Gene sequence data were clustered to explore evolution lineages of H3 antigen of influenza A virus.</p><p><b>METHODS</b>All data of H3 RNA sequence in NCBI Genbank and Influenza sequence database were downloaded and aligned in ClustalX while two step cluster method were applied to explore the data.</p><p><b>RESULTS</b>All sequences were aggregated into ten clusters, while seven of them mainly were human virus. Human virus and avian/other mammal virus were separated into different clusters distinctively, but coexisted into same clusters with swine virus. Time and host distribution were very distinctive in these clusters, but no geographic distribution features were found.</p><p><b>CONCLUSION</b>With the interaction of human immunity system, H3 antigen mutated significantly every 5 - 7 years, and the speed of mutation had accelerated with the application of influenza vaccines in recent years. Mean while, human and swine influenza virus were not separated distinctly between clusters indicating that they had short inheritance distance. Result showed again that swine served as the mixer for antigenic recombination of different influenza virus.</p>