The 2014-15 influenza season saw the emergence of an antigenic drift variant of H3N2 which formed the 3C.2a HA clade. Nasopharyngeal swabs from patients with confirmed influenza A virus infection were used for whole viral genome sequencing to make HA clade calls and identify mutations in the NA (a new glycosylation site, NAg+) and PB1-F2 (H75P mutation). The mutations in NA and PB1-F2 that were present in a subset of clade 3C.2a viruses (NAg+F2P) which came to dominate in the subsequent influenza season. The NAg+F2P genotype viruses were associated with increased wheezing and shortness of breath in infected patients. The use of primary human nasal epithelial cell cultures allowed for more efficient isolation of H3N2 viruses and identified replication differences between H3N2 genotypes. The use of sequencing of clinical samples combined with in vitro analysis of virus replication provided a unique system for identifying and characterizing novel variants of influenza A virus

中文翻译：

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2014-15流感季节H3N2 NA和PB1-F2遗传变异的鉴定及其与疾病症状的关系

2014-15流感季节出现了H3N2抗原性漂移变体，形成了3C.2a HA进化枝。将确诊为甲型流感病毒感染患者的鼻咽拭子用于整个病毒基因组测序，以进行HA进化枝鉴定，并鉴定NA（新糖基化位点NAg +）和PB1-F2（H75P突变）中的突变。NA和PB1-F2的突变存在于进化枝3C.2a病毒（NAg + F2P）的子集中，在随后的流感季节中占主导地位。NAg + F2P基因型病毒与感染患者的喘息和呼吸急促有关。人类鼻上皮细胞原代培养的使用可以更有效地分离H3N2病毒，并鉴定出H3N2基因型之间的复制差异。