ABSTRACT
Foot-and-mouth disease virus (FMDV) is the aetiological angent of a highly contagious viral disease. The complete gene encoding the structural protein of FMDV (P1) was subcloned into expression vector pGEX-KG, resulting in the fusion expression plasmid pKG-P1. After transformed into E. coli BL21(DE3) and induced by IPTG, the results of SDS-PAGE showed that the GST-P1 fusion protein was expressed in high level. The molecular weight of the fusion protein wa 110kD and the expressed products were soluble. Western-blotting was performed to confirm that the expressed fusion protein could specifically react with antiserum against FMDV. The fusion proteins were further purified by GST purification kit and an indirect ELISA (P1-ELISA) based on the purified proteins was developed. Comparison between P1-ELISA and the standard indirect haemagglutinin assay showed the two methods had 87 per cent agreement by detecting 864 serum samples, indicating the purified P1 protein was specific as the antigen of indirect P1-ELISA.
Subject(s)
Capsid Proteins , Genetics , Allergy and Immunology , Escherichia coli , Genetics , Metabolism , Foot-and-Mouth Disease Virus , Genetics , Recombinant Fusion Proteins , Genetics , Allergy and ImmunologyABSTRACT
To enhance the immuogenicity of DNA vaccines expressing the GP5 protein of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), the tegument protein VP22 (encoded by VP22 gene) of Bovine Herpesvirus 1 (BHV-1), which has been demonstrated to exhibit the unusual protein transduction property, was fused to N-terminus of GP5 of DNA vaccine construct pCI-ORF5M, resulting in pCI-VP22-ORF5M expressing VP22-GP5 fusion protein. The expression of VP22-GP5 fusion protein was confirmed by both indirect immunofluorescence assay (IFA) and Western blot. To investigate its immunogenicity, BALB/c mice were immunized with the fusion expression plasmid pCI-VP22-ORF5M and non-fusion expression plasmid pCI-ORF5M, respectively. The GP5-specific ELISA antibodies, neutralizing antibodies and lymphocyte proliferative responses were evaluated at various time points after primary immunization. The results showed that GP5-specific ELISA antibodies, neutralizing antibodies, and lymphocyte proliferative responses induced by DNA vaccine pCI-VP22-ORF5M were higher significantly than those of DNA vaccine pCI-ORF5M, indicating that fusion expression with BHV-1 VP22 significantly enhances the immuogenicity of DNA vaccine expressing the PRRSV GP5 protein, and that this strategy may also be useful to develop more efficient DNA vaccines against other pathogens.
Subject(s)
Animals , Female , Mice , Antigens, Viral , Genetics , Allergy and Immunology , Artificial Gene Fusion , Mice, Inbred BALB C , Porcine Reproductive and Respiratory Syndrome , Random Allocation , Vaccines, DNA , Genetics , Allergy and Immunology , Viral Envelope Proteins , Genetics , Allergy and Immunology , Viral Structural Proteins , Genetics , Viral Vaccines , Genetics , Allergy and ImmunologyABSTRACT
Pseudorabies virus (PRV), an alpha-herpesvirus, has been used as a vector for live-viral animal vaccines. The recombinant PRV TK- / gE- / GP5+, which expressing GP5 of PRRSV, is developed based on the PRV genetic-depleting vaccine-virus strain, TK- / gE- /LacZ+. However, this strain stimulated poorly the vaccinated animals to produce neutralizing antibodies against PRRSV. In order to develop a booster specific immunized response of the PRV recombinant, the ORF5 gene of PRRSV TK- / gE- / LacZ+ was substituted by a modified ORF5 gene, ORF5m. The resultant recombinant PRV, TK- /gE- / GP5m+, was verified by PCR, Southern blotting and Western blotting. TK- / gE- / GP5m+ and TK- / gE- / GP5+ expressed GP5 proteins were inoculated into balb/c mice to evaluate their immunogenicity. The results demonstrated that the amount of neutralization antibodies and cell-immunity responses induced by TK- / gE- /GP5m+ against PRRSV were higher than that of TK- / gE- / GP5+. This study indicated that the new recombinant PRV expressing the modified GP5m protein is a candidate for the development of bivalent genetic engineering vaccines against PRRSV and PRV.
Subject(s)
Animals , Mice , Genetic Vectors , Herpesvirus 1, Suid , Genetics , Allergy and Immunology , Mice, Inbred BALB C , Porcine respiratory and reproductive syndrome virus , Genetics , Allergy and Immunology , Recombinant Fusion Proteins , Genetics , Allergy and Immunology , Recombinant Proteins , Genetics , Allergy and Immunology , Swine , Viral Envelope Proteins , Genetics , Viral Vaccines , Genetics , Allergy and ImmunologyABSTRACT
The cDNA fragment encoding the truncated GP5 and the full-length M protein of Porcine Reproductive and Respiratory Syndrone Virus (PRRSV) were orderly fused to the downstream of glutathione S-transferase (GST) of pGEX-KG expression vector, resulting in the fusion expression plasmid pKG-56. After transformed into E. coli BL21 (DE3) and induced by IPTG, the results of SDS-PAGE showed that the GST-GP5-M fusion protein was expressed in high level. Western-blot was performed to confirm that the expressed fusion protein could specifically react with antiserum against PRRSV. The fusion protein was further purified and used as an antigen to establish a novel PRRSV ELISA diagnose assay (P56-ELISA). Comparison between P56-ELISA and the abroad kit IDEXX-ELISA showed the two methods had 94.1 percent agreement by detecting 205 serum samples, indicating that the indirect P56-ELISA was specific and sensitive. The correlation between virus neutralization antibody of the infected pigs (not convalescent pigs) and antibody response to the fusion protein GP5-M was further studied. The regression function analysis suggested that there was no significant correlation between ELISA antibody response (OD630 nm) to the fusion protein GP5-M in clinical serum and their specific neutralizing titers.
Subject(s)
Animals , Enzyme-Linked Immunosorbent Assay , Escherichia coli , Genetics , Metabolism , Glutathione Transferase , Metabolism , Open Reading Frames , Porcine Reproductive and Respiratory Syndrome , Diagnosis , Allergy and Immunology , Porcine respiratory and reproductive syndrome virus , Genetics , Allergy and Immunology , Recombinant Fusion Proteins , Genetics , Swine , Viral Envelope Proteins , GeneticsABSTRACT
The 1.23 kb DNA fragment encoding the early protein EP0 of pseudorabies virus (PRV) Ea strain was amplified by PCR technique and cloned into pBluescriptII sk+.Three sequencing plasmids containing the partial fragment of the EP0 gene were constructed and the sequences were obtained by Sanger's sequencing technique. Compared with PRV InFh strain, there were multipile site-mutations and a deleted-mutation in the EP0 gene of PRV strain Ea，and the diversity of amino acid residues also existed.Then, the EP0 gene was inserted into an expression vector, pET-28a, fused into the downstream of the 6ΧHis-Tag in frame, to yield the expression plasmid pETEP0. After induction by IPTG, a high expression of fusion protein was obtained, SDS-PAGE analysis and Western blotting showed that the fusion protein was 62kD and the protein was specific to antisera against PRV Ea strain. This indicated that the EP0 gene be expressed in BL21(DE3) and the expression products have immuno-genicity.