ANTIGENIC AND MOLECULAR CHARACTERIZATION OF THE FUSION GLYCOPROTEIN OF RSV

呼吸道合胞病毒是下呼吸道感染的常见病因 婴儿期的疾病该病毒的F糖蛋白已被鉴定 然而，作为保护性免疫应答的重要靶标之一， 免疫力不完全，反复感染。因此，一个主要 该实验室的努力一直是评估抗原的变异， 中和和融合表位，并构建详细的分子 RSV F的表位图。RSV-F融合糖蛋白基因 单克隆抗体抗性突变体已被克隆和测序。 简言之，通过聚合酶链反应扩增病毒mRNA的cDNA拷贝。 反应并克隆到M13中。序列分析确定了 抗原位点A、B和B的中和表位中的酸性残基， C.最显著的取代导致位点A的电荷变化 表位和Garnier分析预测， F糖蛋白的二级结构。与这些发现一致， 含有这种变化的变体表现出小噬斑表型， 这表明功能下降是由于 F糖蛋白的结构修饰。我们还比较 这些病毒在棉鼠体内的复制。几个变种 病毒，包括那些具有小空斑表型的病毒， 与亲本病毒相比，在棉鼠肺中复制的能力。 这表明F糖蛋白可能是决定性因素之一， 毒力和细胞向性。此外，自然发生的 减毒菌株可能存在，并在发展中发挥作用， 完全或部分保护性免疫应答。研究如何 更全面地从这些变异病毒中鉴定RSV-F， 进一步评估抗体对该糖蛋白的反应。

Respiratory syncytial virus is the common cause of lower respiratory tract diseases in infancy. The F glycoprotein of this virus has been identified as one of the important targets of a protective immune response, however, immunity is incomplete and repeated infections occur. Therefore, a major effort of this laboratory has been to evaluate antigenic variation of the neutralization and fusion epitopes and construct a detailed molecular epitope map of RSV F. The genes for the fusion glycoprotein of RSV-F monoclonal antibody resistant mutants have been cloned and sequenced. Briefly, a cDNA copy of viral mRNA was amplified by polymerase chain reaction and cloned into M13. Sequence analysis has identified the amino acid residues in the neutralization epitopes of antigenic sites A, B, and C. The most dramatic substitution results in a change in charge in a site A epitope and Garnier analysis predicts a significant alteration in the secondary structure of the F glycoprotein. Consistent with these findings, variants that contain this change exhibit a small plaque phenotype, suggesting that a decrease in function has occurred as a result of a modification in the structure of the F glycoprotein. We also compared replication of these viruses in the cotton rat. Several of the variant viruses, including those with a small plaque phenotype, had a decreased ability to replicate in cotton rat lungs when compared to the parent virus. This suggests that the F glycoprotein may be one of the determinants of virulence and cellular tropism in vivo. Furthermore, naturally occurring attenuated strains may exist and play a role in the development of a complete o I partial protective immune response. Studies are under way to more completely characterize RSV-F from these variant viruses and to further evaluate the antibody response to this glycoprotein.