Posthumus W P, Lenstra J A, Schaaper W M, van Nieuwstadt A P, Enjuanes L, Meloen R H
Central Veterinary Institute, Lelystad, The Netherlands.
J Virol. 1990 Jul;64(7):3304-9. doi: 10.1128/JVI.64.7.3304-3309.1990.
The amino acid sequences recognized by monoclonal antibodies (MAbs) specific for the antigenic site IV of the spike protein S of transmissible gastroenteritis virus were analyzed by PEPSCAN. All MAbs of group IV recognized peptides from the S region consisting of residues 378 to 390. In addition, the neutralizing MAbs (subgroup IV-A) also bound to peptides from the region consisting of residues 1173 to 1184 and to several other peptides with a related amino acid composition. The contribution of the individual residues of both sequences to the binding of a MAb was determined by varying the length of the peptide and by a consecutive deletion or replacement of parental residues by the 19 other amino acids. The sequence consisting of residues 326 to 558, tested as part of a cro-beta-galactosidase hybrid protein, was antigenic, but the sequence consisting of residues 1150 to 1239 was not. Furthermore, antibodies raised in rabbits against the peptide SDSSFFSYGEIPFGN (residues 377 to 391), but not those raised against the peptide VRASRQLAKDKVNEC (residues 1171 to 1185), recognized the virus and had neutralizing activity. We infer that the epitope of the neutralizing MAbs is composite and consists of the linear sequence SFFSYGEI (residues 380 to 387) with contributions of A, D, K, N, Q, or V residues from other parts of the S molecule. The complex epitope was simulated by synthesizing peptides in which the sequences consisting of residues 380 to 387 and 1176 to 1184 were combined. MAbs of subgroup IV-A recognized the combination peptides two to six times better than the individual sequences. These results may offer prospects for the development of an experimental vaccine.
通过肽扫描分析了针对传染性胃肠炎病毒刺突蛋白S抗原位点IV的单克隆抗体（MAb）所识别的氨基酸序列。IV组的所有单克隆抗体都识别来自S区域中由378至390位残基组成的肽段。此外，中和性单克隆抗体（IV - A亚组）还与由1173至1184位残基组成区域的肽段以及其他几个具有相关氨基酸组成的肽段结合。通过改变肽段长度以及用其他19种氨基酸连续缺失或替换亲本残基，确定了这两个序列中各个残基对单克隆抗体结合的贡献。作为cro-β-半乳糖苷酶杂交蛋白一部分进行测试的由326至558位残基组成的序列具有抗原性，但由1150至1239位残基组成的序列则没有。此外，用针对肽段SDSSFFSYGEIPFGN（377至391位残基）免疫兔子产生的抗体能识别该病毒并具有中和活性，而针对肽段VRASRQLAKDKVNEC（1171至1185位残基）免疫兔子产生的抗体则不能。我们推断，中和性单克隆抗体的表位是复合的，由线性序列SFFSYGEI（380至387位残基）组成，同时S分子其他部分的A、D、K、N、Q或V残基也有贡献。通过合成将由380至387位残基和1176至1184位残基组成的序列组合在一起的肽段来模拟该复合表位。IV - A亚组的单克隆抗体对组合肽段的识别能力比对单个序列强两至六倍。这些结果可能为实验性疫苗的开发提供前景。
