Two novel neutralizing antigenic epitopes of the s1 subunit protein of a QX-like avian infectious bronchitis virus strain Sczy3 as revealed using a phage display peptide library

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• 作者：Nianli Zou^a ; ^c ; ¹ ; Jing Xia^a ; ¹ ; Fuyan Wang^a ; Zhenzhen Duan^a ; Dan Miao^a ; Qigui Yan^a ; ^b ; Sanjie Cao^a ; ^b ; Xintian Wen^a ; ^b ; Ping Liu^a ; ^b ; Yong Huang^a ; ^b ; ^{hyong601@163.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Infectious bronchitis virus (IBV) ; Monoclonal antibodies ; Phage random peptide library ; Neutralizing antigenic epitope
• 刊名：Veterinary Immunology and Immunopathology
• 出版年：2015
• 出版时间：15 November 2015
• 年：2015
• 卷：168
• 期：1-2
• 页码：49-55
• 全文大小：1028 K

文摘

The spike (S) protein of the infectious bronchitis virus (IBV) plays a central role in the pathogenicity, the immune antibody production, serotype and the tissue tropism. In this study, we generate 11 monoclonal antibodies (mAbs) against S1 subunit of IBV Sczy3 strain, and two mAbs 1D5 and 6A12 were positive in indirect ELISA against both His-S1 protein and the purified whole viral antigen. MAb 6A12 and 1D5 could recognized by other 10 IBV strains (IBVs) from five different genotypes, except that 1D5 had a relatively low reaction with two of the 10 tested IBVs. End-point neutralizing assay performed in chicken embro kidney (CEK) cells revealed that the neutralization titer of 6A12 and 1D5 against Sczy3 reached 1:44.7 and 1:40.6, respectively. After screening a phage display peptide library and peptide scanning, we identified two linear B-cell epitopes that were recognized by the mAbs 1D5 and 6A12, which corresponded to the amino acid sequences ⁸⁷PPQGMAW⁹³ and ⁴¹²IQTRTEP⁴¹⁸, respectively, in the IBV S1 subunit. Sequences comparison revealed that epitope ⁴¹²IQTRTEP⁴¹⁸ was conserved among IBVs, while the epitope ⁸⁷PPQGMAW⁹³ was relatively variable among IBVs. The novel mAbs and the epitopes identified will be useful for developing diagnostic assays for IBV infections.