Meyer W J, Wood J M, Major D, Robertson J S, Webster R G, Katz J M
Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38101.
Virology. 1993 Sep;196(1):130-7. doi: 10.1006/viro.1993.1461.
Growth of clinical specimens of influenza viruses in eggs can result in the selection of antigenic variants distinct from corresponding viruses grown in mammalian tissue culture. To evaluate the contribution of host cell selection on the antigenic diversity of human influenza isolates, as seen in annual surveillance studies, viruses grown in embryonated eggs were compared by antigenic and genetic analyses with their mammalian tissue culture-grown counterparts. Clinical specimens were gathered from around the world from late 1987 to 1990 and the antigenicity of isolated viruses was assessed by hemagglutination-inhibition assays using immune ferret sera as is currently performed for routine surveillance and the selection of vaccine strains. In addition, viruses were assessed using a panel of anti-H3 HA monoclonal antibodies. The extent of antigenic variation exhibited by the egg-grown strains was far greater than the relative antigenic homogeneity of the tissue culture-grown viruses. Nucleotide sequence analysis of HA1 gene PCR products of 28 MDCK cell and egg derived pairs allowed identification of amino acid substitutions responsible for the antigenic differences observed and the adaptation to growth in eggs. Among these substitutions was a change at amino acid position 186 of HA1 (Ser in tissue culture viruses and lle in egg-grown viruses) which was observed at relatively high frequency. Egg- and MDCK-grown pairs with this single amino acid difference were classified into distinct antigenic groups by ferret sera raised to WHO reference viruses. Given the additional antigenic diversity observed among egg-grown strains, considerable care should be taken in the selection of reference and vaccine strains grown in eggs. Rapid sequence comparisons of MDCK- and egg-grown viruses allow identification of variants arising through egg selection and will prove to be a useful adjunct to antigenic surveillance for the selection of reference and vaccine strains.
流感病毒临床样本在鸡胚中生长可能会导致产生与在哺乳动物组织培养中生长的相应病毒不同的抗原变体。为了评估宿主细胞选择对人类流感分离株抗原多样性的影响（正如年度监测研究中所观察到的那样），通过抗原分析和基因分析，将在鸡胚中生长的病毒与其在哺乳动物组织培养中生长的对应病毒进行了比较。1987年末至1990年期间从世界各地收集了临床样本，并像目前进行常规监测和疫苗株选择那样，使用免疫雪貂血清通过血凝抑制试验评估分离病毒的抗原性。此外，使用一组抗H3 HA单克隆抗体对病毒进行了评估。在鸡胚中生长的毒株所表现出的抗原变异程度远远大于在组织培养中生长的病毒相对的抗原同质性。对28对来源于MDCK细胞和鸡胚的毒株的HA1基因PCR产物进行核苷酸序列分析，能够鉴定出导致所观察到的抗原差异以及适应在鸡胚中生长的氨基酸替换。在这些替换中，HA1氨基酸位置186处的变化（组织培养病毒中为丝氨酸，鸡胚中生长的病毒中为异亮氨酸）出现频率相对较高。具有这一单氨基酸差异的鸡胚和MDCK细胞生长的毒株，被用针对世界卫生组织参考病毒产生的雪貂血清分为不同的抗原组。鉴于在鸡胚中生长的毒株中观察到额外的抗原多样性，在选择在鸡胚中生长所获得的参考株和疫苗株时应格外小心。对MDCK细胞和鸡胚生长的病毒进行快速序列比较，能够鉴定出因鸡胚选择而产生的变体，这将被证明是抗原监测中选择参考株和疫苗株的有用辅助手段。
