title: Intracellularly expressed nanobodies against non-structural protein 4 of porcine reproductive and respiratory syndrome virus inhibit virus replication.
abstract: OBJECTIVE
  To isolate specific nanobodies to porcine reproductive and respiratory syndrome virus (PRRSV) non-structural protein 4 (Nsp4) and investigate their potential antiviral activities.
  
  
  RESULTS
  Three PRRSV Nsp4-specific nanobodies were isolated from a phage display library of the variable domains of camelid heavy chain-only antibodies. Nanobody genes were introduced into MARC-145 cells using lentivirus vectors to establish cell lines stably expressing nanobodies. These intracellularly expressed nanobodies were tested for interaction with PRRSV-encoded Nsp4 within PRRSV-infected MARC-145 cells. Nb41 and Nb43 intrabodies each potently inhibited PRRSV replication, protected MARC-145 cells from PRRSV-induced cytopathic effect and fully blocked PRRSV replication at an MOI of 0.001 or lower.
  
  
  CONCLUSIONS
  Intracellularly expressed Nb41 and Nb43 potently suppressed PRRSV replication in MARC-145 cells. Nanobodies hold great potential for development as novel antiviral treatments for PRRSV infection.
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liang
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Duan
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
authors.forename: Xiangpeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
authors.forename: Shuqi
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China. zhouem@nwsuaf.edu.cn.
authors.forename: En-Min
authors.identifier: http://orcid.org/0000-0001-8942-013X
authors.initials: EM
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000276:immunology / Q000494:pharmacology*; D002460:Cell Line; D002522:Chlorocebus aethiops; D019316:Porcine respiratory and reproductive syndrome virus / Q000187:drug effects*; D061905:Single-Domain Antibodies / Q000276:immunology / Q000494:pharmacology*; D017361:Viral Nonstructural Proteins / Q000276:immunology*; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D061905:Single-Domain Antibodies; D017361:Viral Nonstructural Proteins
keywords: Intrabody; Lentivirus; Nanobody; Non-structural protein 4; Porcine reproductive and respiratory syndrome virus; Single-domain antibody