Expression of CSFV E2 Protein in Eukaryotic Cells and Characterization of
Immunity in Animals
The viral envelope glycoprotein E2 is major target for eliciting protective antibodies against CSFV in infected animals. To express CSFV E2 protein on eukaryotic cells, the recombinant retroviral vector pBabe-puro-E2 was constructed by inserting full-length CSFV Shimen strain E2 region into pBabe-puro. Both of the recombinant retroviral vector and pVSVg plasmid were transfected eukaryotic 293GP cells using method of calcium phosphate coprecipitation in where thus the recombinant pseudovirus were packaged and propagated. The PK-15 cells were infected with recombinant pseudovirus. The recombinant PK-15 cells were screened by spytomycin resistance and the expression of E2 protein was detected by Flow Cytometer (FCM). The activity of recombinant E2 protein to induce immune responses was evaluated in Balb/c mice and unvaccinated pigs. The results showed that CSFV E2 protein was successfully expressed on PK-15 cells membrane. Anti-E2 antibody induced in experimental animals was detected by Enzyme Linked Immunosorbent Assay (ELISA). Moreover, the virus challenge indicated that the immunized pigs generated effective protection against virulent CSFV. These results indicated that a retroviral-based E2-vaccine is able to induce high level of specific antibodies and exhibits similar protective capability with that induced by the C-strain.