{"doi":"10.3390/v11100972","title":"The S2 Subunit of QX-type Infectious Bronchitis Coronavirus Spike Protein Is an Essential Determinant of Neurotropism","abstract":"<jats:p>Some coronaviruses (CoVs) have an extra furin cleavage site (RRKR/S, furin-S2′ site) upstream of the fusion peptide in the spike protein, which plays roles in virion adsorption and fusion. Mutation of the S2′ site of QX genotype (QX-type) infectious bronchitis virus (IBV) spike protein (S) in a recombinant virus background results in higher pathogenicity, pronounced neural symptoms and neurotropism when compared with conditions in wild-type IBV (WT-IBV) infected chickens. In this study, we present evidence suggesting that recombinant IBV with a mutant S2′ site (furin-S2′ site) leads to higher mortality. Infection with mutant IBV induces severe encephalitis and breaks the blood–brain barrier. The results of a neutralization test and immunoprotection experiment show that an original serum and vaccine can still provide effective protection in vivo and in vitro. This is the first demonstration of IBV-induced neural symptoms in chickens with encephalitis and the furin-S2′ site as a determinant of neurotropism.</jats:p>","journal":"Viruses","year":2019,"id":605292,"datarank":0.637274286307404,"base_score":4.248495242049359,"endowment":4.248495242049359,"self_citation_contribution":0.637274286307404,"citation_network_contribution":0.0,"self_endowment_contribution":0.637274286307404,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":69,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":961330,"name":"Ye Zhao","orcid":"0000-0003-1384-6024","position":1,"is_corresponding":false},{"id":1193834,"name":"Gang Xu","orcid":"0009-0005-0351-4263","position":2,"is_corresponding":false},{"id":1553370,"name":"Keran Zhang","orcid":null,"position":3,"is_corresponding":false},{"id":1553371,"name":"Wenfeng Jia","orcid":null,"position":4,"is_corresponding":false},{"id":1553372,"name":"Yali Sun","orcid":null,"position":5,"is_corresponding":false},{"id":404136,"name":"Jing Zhao","orcid":"0000-0001-8973-0429","position":6,"is_corresponding":false},{"id":225731,"name":"Jia Xue","orcid":"0000-0001-8683-621X","position":7,"is_corresponding":false},{"id":1553373,"name":"Yanxin Hu","orcid":null,"position":8,"is_corresponding":false},{"id":1288861,"name":"Guozhong Zhang","orcid":"0000-0002-8200-312X","position":9,"is_corresponding":false},{"id":1553369,"name":"Jinlong Cheng","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"The S2 Subunit of QX-type Infectious Bronchitis Coronavirus Spike Protein Is an Essential Determinant of Neurotropism","abstract":"<jats:p>Some coronaviruses (CoVs) have an extra furin cleavage site (RRKR/S, furin-S2′ site) upstream of the fusion peptide in the spike protein, which plays roles in virion adsorption and fusion. Mutation of the S2′ site of QX genotype (QX-type) infectious bronchitis virus (IBV) spike protein (S) in a recombinant virus background results in higher pathogenicity, pronounced neural symptoms and neurotropism when compared with conditions in wild-type IBV (WT-IBV) infected chickens. In this study, we present evidence suggesting that recombinant IBV with a mutant S2′ site (furin-S2′ site) leads to higher mortality. Infection with mutant IBV induces severe encephalitis and breaks the blood–brain barrier. The results of a neutralization test and immunoprotection experiment show that an original serum and vaccine can still provide effective protection in vivo and in vitro. 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