NUCLEOTIDE CHANGES RESPONSIBLE FOR LOSS OF NEUROINVASIVENESS IN JAPANESE ENCEPHALITIS-VIRUS NEUTRALIZATION-RESISTANT MUTANTS
NUCLEOTIDE CHANGES RESPONSIBLE FOR LOSS OF NEUROINVASIVENESS IN JAPANESE ENCEPHALITIS-VIRUS NEUTRALIZATION-RESISTANT MUTANTS
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DOI：
10.1016/0042-6822(91)90471-m
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发表时间：
1991-03-01
期刊：
影响因子：
3.7
通讯作者：
GOULD, EA
中科院分区：
文献类型：
--
作者：
CECILIA, D;GOULD, EA
日本脑炎病毒砂拉越株（1E-Sar）在腹膜内接种时对 3 周龄的小鼠具有毒性。确定了该病毒的包膜糖蛋白（E）的核苷酸序列，并将其与其他四种毒株的已发表序列进行了比较。存在几个沉默的核苷酸差异和五个密码子变化。制备并表征了针对 JE-Sar 病毒 E 蛋白的单克隆抗体 (MAb)。选择 1E-Sar 的 MAb 抗性突变体来确定 E 蛋白基因的突变是否会影响其对小鼠的毒力。使用五种不同的单克隆抗体分离出八个突变体，这些单克隆抗体可识别 E 蛋白上的病毒特异性或基团反应性表位。突变体失去了选择 MAb 的完全或部分反应性。腹膜内接种后，一些 3 周大的小鼠表现出毒力下降。两种病毒（r27 和 r30）在 2 周大的小鼠中也显示出毒力降低。当颅内接种时，JE-Sar 和衍生突变体对小鼠的毒力相当。突变体r30而非r27在成年小鼠中诱导了针对母病毒颅内攻击的保护性免疫。然而，r27-2确实诱导了针对自身的保护性免疫。对突变体 E 编码区的核苷酸测序揭示了 r30 和 r27 中的单碱基变化，导致 r30 中第 270 位的异亮氨酸变为丝氨酸，以及 r27 中第 333 位的甘氨酸从甘氨酸变为天冬氨酸。突变体诱导保护性免疫的能力改变与使用 Protean II 程序进行计算机分析预测的免疫原性变化一致。
The Sarawak strain of Japanese encephalitis virus (1E-Sar) is virulent in 3-week-old mice when inoculated intraperitoneally. The nucleotide sequence for the envelope glycoprotein (E) of this virus was determined and compared with the published sequences of four other strains. There were several silent nucleotide differences and five codon changes. Monoclonal antibodies (MAbs) against the E protein of JE-Sar virus were prepared and characterized. MAb-resistant mutants of 1E-Sar were selected to determine if mutations in the E protein gene could affect its virulence for mice. Eight mutants were isolated using five different MAbs that identified virus-specific or group-reactive epitopes on the E protein. The mutants lost either complete or partial reactivity with selecting MAb. Several showed decreased virulence in 3-week-old mice after intraperitoneal inoculation. Two (r27 and r30) also showed reduced virulence in 2-week-old mice. JE-Sar and the derived mutants were comparable in their virulence for mice, when inoculated intracranially. Mutant r30 but not r27 induced protective immunity in adult mice against intracranial challenge with parent virus. However, r27-2 did induce protective immunity against itself. Nucleotide sequencing of the E coding region for the mutants revealed single base changes in both r30 and r27 resulting in a predicted change from isoleucine to serine at position 270 in r30 and from glycine to aspartic acid at position 333 in r27. The altered capacity of the mutants to induce protective immunity is consistent with the immunogenicity changes predicted by computer analysis using the Protean II program.