title: In vivo characterization of chimeric PCV DNA clones containing heterogeneous capsid protein nuclear localization signals (NLS).
abstract: BACKGROUND
  PCV ORF2 capsid protein was predicted to contribute to the control of replication via an interaction between the Cap and Rep proteins in the nucleoplasm. We previously showed that the nuclear localization signal (NLS) on the capsid protein plays an accessory role in the replication of PCV in vitro. To further evaluate the in vivo characteristics of NLS-chimeric PCV DNA clones, BALB/C mice were inoculated intranasally and intraperitoneally with the DNA clones.
  
  
  RESULTS
  As expected, no gross lesions were detected during the study of the inoculated animals. The chimeric PCV12-, PCV1-NLS2- and PCV2-NLS1-inoculated animals had significantly fewer and less severe histopathological lesions in lymphoid tissues than the PCV2-inoculated animals (P < 0.05). PCV12 induced a specific antibody response against PCV2 ORF2 comparable to that induced by wild-type PCV2 but demonstrated a shorter period of viremia and much lower level of virus loads in sera than those in PCV2-inoculated mice. Remarkably, the PCV2-NLS1 and PCV1-NLS2 chimeras replicated in inoculated mice and induced specific antibody responses but failed to produce viral antigens in the lymph nodes or a detectable viremia.
  
  
  CONCLUSIONS
  The chimeric PCV2-NLS1 and PCV1-NLS2 demonstrated a lower replication level as compared with wild type of PCV2 or PCV1 in vivo, suggesting that ORF2 NLSs played an accessory role in PCV replication. The chimeric PCV12 is a good candidate for vaccination against PCV2 infection.
authors.affiliation: Zhejiang Entry-Exit Inspection and Quarantine Bureau, 126 Fuchun Road, Hangzhou, 310016, China.
authors.forename: Jiangbing
authors.initials: J
authors.lastname: Shuai
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhang
authors.forename: Wujian
authors.initials: W
authors.lastname: Chen
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.forename: Shan
authors.initials: S
authors.lastname: Wu
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: He
authors.forename: Weihuan
authors.initials: W
authors.lastname: Fang
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D018173:Circoviridae Infections / Q000276:immunology / Q000473:pathology / Q000821:virology; D017925:Circovirus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D004279:DNA, Viral / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D019913:Nuclear Localization Signals / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D014779:Virus Replication
chemical_list: D000914:Antibodies, Viral; D036022:Capsid Proteins; D004279:DNA, Viral; D019913:Nuclear Localization Signals; D011994:Recombinant Proteins