Sequencing and rescuing a highly virulent classical swine fever virus: Chinese strain cF114 from a full-length cDNA clone

The complete nucleotide sequence of classical swine fever virus (CSFV) strain cF114 (F114 strain propagated on PK-15 cells) was cloned by RT-PCR. The analyses of nucleotide and amino acids identity between cF114 and F114, Brescia, Alfort or C strain were 99.41%, 96.80%, 86.03%, 95.70% and 99.28%, 98.54%, 93.33%, 97.41% respectively. The cDNA fragments with correct sequence were ligated into a full-length cDNA and inserted into pMC18 plasmid (pMC12297). A full-length infectious viral RNA was synthesized by runoff transcription and transfected to PK15 cells. Viruses were recovered from transfected cells which wese titrated on PK-15 cells by endpoint dilution and indirect immunofluorescence with a CSFV-specific monoclonal antibody. The antigenicity and replication kinetics of the plasmid-derived virus (vM12297) were similar to the parental virus in vitro. The E01 or E2 gene was replaced with the genes from strain C and the pM/CE01 and pM/CE2 with chimeric full-length cDNA of cF114 were generated. The infectious viruses were obtained from pM/CE01 and pM/CF2. Both of the chimeric viruses can infect PK-15, SK-6 and primary testicle cell of swine. The chimeric viruses can grow to a titer of 8X10(5) F-PFU/mL. These results are very important for understanding the genes related to the CSFV propagation and pathogenesis.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000183662600015&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Multidisciplinary SciencesSCI(E)1ARTICLE111124-11284