Nakagawa N, Kubota R, Morikawa S, Nakagawa T, Baba K, Okuno Y
Division of Virology, Department of Public Health, Osaka Prefectural Institute of Public Health, Nakamichi, Higashinari-ku, Osaka, Japan.
J Med Virol. 2001 Dec;65(4):745-50. doi: 10.1002/jmv.2099.
During the 1998-1999 influenza season, two distinct influenza B virus Yamagata group strains were isolated from the patients of a private clinic. Each responded differently to monoclonal antibodies (Mabs) 5H4 and 8B3 on staining, and hemagglutination inhibition and neutralizing tests. When the analysis of nucleotide sequences was undertaken, the identity of deduced amino acid sequences of the HA1 region was 94%, which suggested that they derived from different strains. They were termed 5H4-responding strains and 5H4-nonresponding strains, respectively. The analysis of laboratory-induced antigenic variants suggested that the amino acid at position 149 is important to the reactivity to 5H4. This residue was "Arg" in 5H4-responding strains and "Lys" in nonresponding strains. During the 1998-1999 season, a total of 100 influenza B virus strains were isolated and 5H4-responding strains were the major type (94 strains). In the 1999-2000 influenza season, only two influenza B virus strains were isolated. Neither responded to 5H4. However, analysis of the deduced amino acid sequences of the HA1 region suggested that one of the two strains was derived from the 5H4-responding strains of the previous season. The amino acid residue at position 149 was "Lys" in place of "Arg." These observations suggested that 5H4-nonresponding strains will increase in coming seasons.
在1998 - 1999年流感季节，从一家私人诊所的患者中分离出两种不同的乙型流感病毒山形株系。在染色、血凝抑制和中和试验中，它们对单克隆抗体（Mabs）5H4和8B3的反应各不相同。当进行核苷酸序列分析时，HA1区域推导的氨基酸序列的同一性为94%，这表明它们源自不同的株系。它们分别被称为5H4反应株和5H4无反应株。对实验室诱导的抗原变异体的分析表明，第149位的氨基酸对与5H4的反应性很重要。该残基在5H4反应株中为“精氨酸（Arg）”，在无反应株中为“赖氨酸（Lys）”。在1998 - 1999年季节，共分离出100株乙型流感病毒株，其中5H4反应株是主要类型（94株）。在1999 - 2000年流感季节，仅分离出两株乙型流感病毒株。两者均对5H4无反应。然而，对HA1区域推导的氨基酸序列的分析表明，这两株中的一株源自上一季的5H4反应株。第149位的氨基酸残基为“赖氨酸（Lys）”而非“精氨酸（Arg）”。这些观察结果表明，5H4无反应株在未来季节将会增加。
