Vasfi Marandi M, Malekan M, Ranjbar M M, Dadashpour Davachi N, Alamian S
Department of Poultry Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
Department of Animal Virology, Research and Diagnosis, Razi Vaccine and Serum Research Institute, Agricultural Research, Education, and Extension Organization(AREEO), Karaj, Iran.
Arch Razi Inst. 2018 Sep;73(3):183-198. doi: 10.22092/ari.2018.120305.1192. Epub 2018 Sep 1.
Infectious bronchitis (IB) is an acute, highly contagious, and economically important viral disease of chickens. The S1 subunit from Spike (S) protein plays the major role in protective immunity and is involved in the host-virus interactions, as well as infectious bronchitis virus (IBV) serotyping. Aim of the present study was multi-aspect analysis of the molecular and immunological features of 5' part belonging to the S1 glycoprotein sequence of Iranian 793/B IBV strain isolates. This might ideally help in characterization, prevention, and vaccine development. The tissue samples were prepared, followed by virus isolation, reverse transcription polymerase chain reaction and restriction fragment length polymorphism analysis. In addition, sequencing and registration of the sequences in the National Center for Biotechnology Information were performed. Moreover, 12 sequences were retrieved from Fars province, Iran. The next steps included evaluation of conservation/variability along the sequences, phylogenetic analysis, estimation of the average evolutionary divergence over all the sequence pairs, predicting the phosphorylation/N-glycosylation/palmitoylation sites, and the final analysis of antigenicity. The findings of alignment, entropy plot, and pairwise similarity analysis revealed 17 hypervariable regions. The isolates belonging to Tehran were clustered in phylogenetic tree, and the most similar isolates to them were ADW11182 and ADW11183. Location of some of the N-glycosylation/phosphorylation/palmitoylation points indicated that these sites were conserved among the isolates. Furthermore, the frequency of epitopes and their scores reflect the high immunogenicity of S1 protein in 793/B serotype. Analysis of the primary and secondary structures demonstrated that their parameters had variable values and were different regarding the number and location of α-helix, β-strand, and coils. According to our findings, the Iranian isolates of 793/B serotype change their molecular characteristics during time and in different geographical regions. These alterations might account for failure in prevention programs and differences in virulence and pathogenicity.
传染性支气管炎（IB）是鸡的一种急性、高度传染性且具有重要经济意义的病毒性疾病。来自刺突（S）蛋白的S1亚基在保护性免疫中起主要作用，参与宿主 - 病毒相互作用以及传染性支气管炎病毒（IBV）血清分型。本研究的目的是对伊朗793/B IBV毒株分离株S1糖蛋白序列5'部分的分子和免疫特征进行多方面分析。这可能有助于理想地进行特征描述、预防和疫苗开发。制备组织样本，随后进行病毒分离、逆转录聚合酶链反应和限制性片段长度多态性分析。此外，还进行了序列测序并在国家生物技术信息中心进行了序列登记。此外，从伊朗法尔斯省检索到12个序列。接下来的步骤包括评估序列中的保守性/变异性、系统发育分析、估计所有序列对的平均进化差异、预测磷酸化/ N - 糖基化/棕榈酰化位点以及最终的抗原性分析。比对、熵图和成对相似性分析的结果揭示了17个高变区。属于德黑兰的分离株在系统发育树中聚类，与它们最相似的分离株是ADW11182和ADW11183。一些N - 糖基化/磷酸化/棕榈酰化位点的位置表明这些位点在分离株中是保守的。此外，表位的频率及其得分反映了793/B血清型中S1蛋白的高免疫原性。一级和二级结构分析表明，它们的参数具有可变值，并且在α - 螺旋、β - 链和卷曲的数量和位置方面有所不同。根据我们的研究结果，伊朗793/B血清型的分离株在不同时间和不同地理区域会改变其分子特征。这些改变可能是预防计划失败以及毒力和致病性差异的原因。
