Hovanec D L, Air G M
Virology. 1984 Dec;139(2):384-92. doi: 10.1016/0042-6822(84)90384-2.
Antigenic variation among influenza B viruses is different from that of influenza A in several ways. Antigenic shift has not been observed, distinct antigenic variants of influenza B cocirculate, and antigenically similar viruses have been isolated many years apart. To study the mechanism of antigenic drift in influenza B viruses, monoclonal antibodies were used to select antigenic variants of B/Hong Kong/8/73 virus hemagglutinin (HA). Analyses of the nucleotide sequences of the HA gene of B/Hong Kong/8/73 and the eight variants identified specific regions of the influenza B HA molecule involved in antigenicity, and enabled antigenic mapping data to be correlated with the structure of the protein. The altered amino acids in the variants, when compared to the HA of A/Aichi/2/68, were found in two of the four antigenic regions previously identified for type A viruses. In addition, four of the eight variants showed multiple nucleotide changes some of which gave rise to double amino acid changes. In addition, in the present study monoclonal antibodies which belong to the same antigenic group recognize amino acid changes in regions corresponding to antigenic sites A and B of the H3 HA. These results are in contrast to those obtained with HA variants of A/Memphis/1/71 virus. In the influenza A studies only single amino acid changes were found and these correlated well with the three-dimensional structure as determined by D. C. Wiley, I. A. Wilson, and J. J. Skehel, (1981, Nature (London) 289, 366-373); monoclonal antibodies which recognized one region did not recognize any of the other antigenic sites. Our results suggest that although the basic three-dimensional structure of the influenza B HA may be similar to that of A viruses, the B HA molecule may be folded in a more compact manner so that antigenic sites A and B are in closer proximity to each other than in the H3 structure.
乙型流感病毒的抗原变异在几个方面不同于甲型流感病毒。尚未观察到抗原转变，乙型流感病毒的不同抗原变体同时流行，并且抗原性相似的病毒在相隔多年后仍被分离出来。为了研究乙型流感病毒抗原漂移的机制，使用单克隆抗体筛选了B/香港/8/73病毒血凝素（HA）的抗原变体。对B/香港/8/73及其八个变体的HA基因核苷酸序列进行分析，确定了乙型流感病毒HA分子中涉及抗原性的特定区域，并使抗原图谱数据能够与蛋白质结构相关联。与A/爱知/2/68的HA相比，变体中发生改变的氨基酸位于先前为甲型病毒确定的四个抗原区域中的两个区域。此外，八个变体中的四个显示出多个核苷酸变化，其中一些导致了双氨基酸变化。此外，在本研究中，属于同一抗原组的单克隆抗体识别与H3 HA的抗原位点A和B相对应区域中的氨基酸变化。这些结果与用A/孟菲斯/1/71病毒的HA变体获得的结果形成对比。在甲型流感研究中，仅发现了单个氨基酸变化，并且这些变化与D.C.威利、I.A.威尔逊和J.J.斯凯尔（1981年，《自然》（伦敦）289, 366 - 373）确定的三维结构密切相关；识别一个区域的单克隆抗体不识别任何其他抗原位点。我们的结果表明，尽管乙型流感病毒HA的基本三维结构可能与甲型病毒相似，但乙型HA分子可能以更紧凑的方式折叠，使得抗原位点A和B比H3结构中彼此更接近。
