Gohil Devanshi, Kothari Sweta, Shinde Pramod, Meharunkar Rhuta, Warke Rajas, Chowdhary Abhay, Deshmukh Ranjana
Department of Virology and Immunology, Haffkine Institute for Training, Research and Testing, Acharya Donde Marg, Parel, Mumbai, Maharashtra, 400012, India.
Department of Bioinformatics, Guru Nanak Khalsa College, Mumbai, Maharashtra, India.
Curr Microbiol. 2017 Aug;74(8):899-907. doi: 10.1007/s00284-017-1262-6. Epub 2017 May 11.
Pandemic influenza A (H1N1) 2009 virus was first detected in India in May 2009 which subsequently became endemic in many parts of the country. Influenza A viruses have the ability to evade the immune response through its ability of antigenic variations. The study aims to characterize influenza A (H1N1) pdm 09 viruses circulating in Mumbai during the pandemic and post-pandemic period. Nasopharyngeal swabs positive for influenza A (H1N1) pdm 09 viruses were inoculated on Madin-Darby canine kidney cell line for virus isolation. Molecular and phylogenetic analysis of influenza A (H1N1) pdm 09 isolates was conducted to understand the evolution and genetic diversity of the strains. Nucleotide and amino acid sequences of the HA gene of Mumbai isolates when compared to A/California/07/2009-vaccine strain revealed 14 specific amino acid differences located at the antigenic sites. Amino acid variations in HA and NA gene resulted in changes in the N-linked glycosylation motif which may lead to immune evasion. Phylogenetic analysis of the isolates revealed their evolutionary position with vaccine strain A/California/07/2009 but had undergone changes gradually. The findings in the present study confirm genetic variability of influenza viruses and highlight the importance of continuous surveillance during influenza outbreaks.
2009年甲型H1N1流感大流行病毒于2009年5月首次在印度被检测到，随后在该国许多地区成为地方病。甲型流感病毒有能力通过其抗原变异能力逃避免疫反应。本研究旨在对甲型H1N1流感大流行病毒在大流行期间和大流行后在孟买传播的病毒进行特征分析。对甲型H1N1流感大流行病毒呈阳性的鼻咽拭子接种到Madin-Darby犬肾细胞系上进行病毒分离。对甲型H1N1流感大流行病毒分离株进行分子和系统发育分析，以了解这些毒株的进化和遗传多样性。孟买分离株的血凝素（HA）基因的核苷酸和氨基酸序列与A/加利福尼亚/07/2009疫苗株相比，在抗原位点发现了14个特定的氨基酸差异。HA和神经氨酸酶（NA）基因中的氨基酸变异导致了N-连接糖基化基序的变化，这可能导致免疫逃避。对分离株的系统发育分析揭示了它们与疫苗株A/加利福尼亚/07/2009的进化位置，但已逐渐发生变化。本研究结果证实了流感病毒的遗传变异性，并强调了在流感爆发期间持续监测的重要性。
