OBJECTIVEGene sequence data were clustered to explore evolution lineages of H3 antigen of influenza A virus.

METHODSAll data of H3 RNA sequence in NCBI Genbank and Influenza sequence database were downloaded and aligned in ClustalX while two step cluster method were applied to explore the data.

RESULTSAll sequences were aggregated into ten clusters, while seven of them mainly were human virus. Human virus and avian/other mammal virus were separated into different clusters distinctively, but coexisted into same clusters with swine virus. Time and host distribution were very distinctive in these clusters, but no geographic distribution features were found.

CONCLUSIONWith the interaction of human immunity system, H3 antigen mutated significantly every 5 - 7 years, and the speed of mutation had accelerated with the application of influenza vaccines in recent years. Mean while, human and swine influenza virus were not separated distinctly between clusters indicating that they had short inheritance distance. Result showed again that swine served as the mixer for antigenic recombination of different influenza virus.

Antigenic Variation ; genetics ; Antigens, Viral ; genetics ; Cluster Analysis ; Evolution, Molecular ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Hemagglutinins, Viral ; genetics ; immunology ; Humans ; Influenza A virus ; genetics ; immunology ; Mutation ; Sequence Analysis, DNA ; Viral Envelope Proteins ; genetics

The Fusion (F) and Haemagglutinin-Neuraminidase (HN) genes of Newcastle disease virus (NDV) and the glycoprotein B (gB) gene of infectious laryngothracheitis virus (ILTV) as well as a LacZ reporter gene were all inserted into a nonessential gene of fowlpox virus (FPV) 017 strain by homologous recombination. The NDV and ILTV genes were each under the control of a fowlpox virus immediate early/late promoter (LP2EP2) while the LacZ reporter gene expression cassette was regulated by a P11 late promoter. A recombinant FPV harboring the F, HN and gB genes as well as the LacZ gene, designated as rFPV-F/HN/gB/LacZ, was obtained after ten cycles of blue plaque purification. The presence of the NDV and ILTV genes was confirmed by PCR. The expression of the recombinant proteins in rFPV-F/HN/gB/LacZ were characterized by Western blot (F and gB proteins) and indirect immunofluorescence test (F, HN and gB proteins). The results demonstrated that all four foreign proteins, which were encoded within a 10 kb gene fragment, could be expressed authentically and efficiently. Compared to the parental virus, rFPV-F/HN/gB/LacZ showed no obvious difference with respect to virus replication and cytopathogenic effects in chicken embryo fibroblasts (CEF) cell culture. Overall, our work suggests that FPV can be a useful live virus vector for the expression of multi- foreign genes against multiple avian pathogens.
Animals ; Cloning, Molecular ; Fibroblasts ; virology ; Fowlpox virus ; genetics ; Gene Expression ; Genetic Engineering ; methods ; HN Protein ; genetics ; Herpesvirus 1, Gallid ; genetics ; physiology ; Newcastle disease virus ; genetics ; physiology ; Plasmids ; genetics ; Transfection ; Viral Envelope Proteins ; genetics ; Viral Fusion Proteins ; genetics

The artificial 5-helix can inhibit the formation of trimer-of-hairpins structure during the course of HIV-directed membrane fusion and then inhibit human immunodeficiency virus (HIV) infecting target cells. But 5-helix was apt to form inclusion body when expressed directly in prokaryotic cell and was difficult to renature, which causes inconvenience to future study. We found a proper expression vector by simulating protein structure. We simulated its proper conformation in two vectors pGEX-6P-1 and pET44b by homology modeling. The contrast of conformations showed that the energy of salvation of its fusion protein with NusA in vector pET44b was higher than its fusion protein with glutathione-S-transferase (GST) in pGEX-6P-1 and its restriction site lay on the surface of its fusion protein in vector pET44b. 5-helix gene was amplified from pGEX-6P-1-5H by PCR, and was ligated to pET44b to construct recombinant vector pET44b-PSP-5Helix after tested correctly by enzymes digestion. The recombinant vector was transformed into Escherichia coli BL21 (DE3) to express 5-helix protein at different temperatures. Aim protein was purified with Ni column and GST column, and was determined by SDS-PAGE. Then the purified 5 -Helix was used to test the inhibitive activity of pseudo HIV virus infecting GHOST-CXCR4. Results show that its fusion protein with NusA can be effectively soluble expressed and easier to be cleaved, and that the purified 5-helix can efficiently inhibit pseudo HIV virus infecting GHOST-CXCR4 and its IC50 value is (22.77 +/- 5.64) nmol/L, which lay the foundation to further discuss the application in HIV-1 infection.
Carrier Proteins ; biosynthesis ; genetics ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; HIV Envelope Protein gp41 ; metabolism ; HIV-1 ; genetics ; Peptides ; genetics ; Repetitive Sequences, Nucleic Acid ; genetics ; Viral Fusion Proteins ; genetics ; Virus Internalization ; drug effects

FMDV 2A peptide was introduced as a linker between GP5 and M protein of porcine reproduction and respiratory syndrome virus (PRRSV) to allow automatic self-cleavage the polyproteins. This strategy simultaneously displayed the neutralizing action of GP5 protein and cell-mediated immunity of M protein. We put them into the expression cassette of adenovirus vector. The results of RT-PCR, IFA and Western blotting showed that GP5 and M protein were not only expressed correctly, but also self-cleavaged and assemble heterodimers formation. To detect the advantages of rAd-GP5-2A-M, we also constructed some other recombinant adenoviruses (rAd-GP5, rAd-M and rAd-GP5-M) as control. After inoculated subcutaneously into BALB/c mice, the four recombinant adenoviruses can induce PRRSV-specific antibodies and cell-mediated immune response, but the level of humoral and cell-mediated immune response against PRRSV induced by rAd-GP5-2A-M is the strongest among the four recombinant adenoviruses. All of these suggested that it is possible to develop one multi-gene engineering vaccine utilizing FMDV 2A peptide, and also provided a novel strategy for developing other viral disease vaccine.
Adenoviridae ; genetics ; metabolism ; Animals ; Female ; Immunization ; Mice ; Mice, Inbred BALB C ; Recombinant Fusion Proteins ; genetics ; immunology ; metabolism ; Swine ; Vaccines, Synthetic ; immunology ; Viral Envelope Proteins ; genetics ; immunology ; metabolism ; Viral Matrix Proteins ; genetics ; immunology ; metabolism ; Viral Vaccines ; immunology

OBJECTIVETo observe the ability of dengue virus type 1-4 envelope domain III fusion protein to inhibit virus infection and analyze the neutralizing ability of polyclonal antibodies against rE III.

METHODSAfter being connected by linker peptide, E III protein of Dengue virus serotypes 1-4 were expressed in E coli BL21 (DE3) then purified. Fusion proteins were verified by Western Blot and ELISA. Rabbits were immunized with fusion proteins to produce anti-rE III serum. The activity of anti-rE III serum were detected through indirect immunofluorescence assay test. Inhibition of dengue virus type 1 to 4 infection in BHK-21 cells by rE III fusion protein were tested. Neutralizing activity of anti-rE III serum was analyzed.

RESULTSDengue virus type 1 to 4 envelope domain III recombinant fusion protein was expressed in E coli BL21 and purified successfully. Then rE III fusion protein and anti-rE III serum were analyzed respectively and rE III fusion protein can effectively inhibit dengue virus type 1 to 4 from infecting BHK cells. The anti-rE III serums can neutralize dengue virus type 1 to 4 but with different neutralizing titer.

CONCLUSIONDengue virus type 1-4 envelope domain III fusion protein can directly inhibit DV infection. Antibodies induced by rE III fusion proteins can neutralize dengue virus type 1-4.

Animals ; Blotting, Western ; Cells, Cultured ; Dengue Virus ; classification ; drug effects ; growth & development ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; genetics ; Gene Fusion ; genetics ; Gene Products, env ; genetics ; metabolism ; Immunization ; Rabbits ; Recombinant Fusion Proteins ; genetics ; immunology ; metabolism ; pharmacology ; Recombinant Proteins ; biosynthesis ; pharmacology ; Viral Envelope Proteins ; genetics ; immunology ; metabolism ; Virus Replication ; drug effects ; physiology

The M protein gene of porcine reproductive and respiratory syndrome virus amplified by PCR was tandem linked with its GP5 gene in shuttle vector in correct frame, resulting in shuttle vector pShuttle-CMV-M-GP5. The positive clone was identified by PCR and further confirmed by sequencing. The constructed plasmid was linearized with Pme I and co-transformed BJ5183 host bacteria with pAdEasy-1 to produce recombinant adenovirus DNA by homologous recombination. Then the adenovirus DNA was linearized with Pac I and transfected into HEK-293A cells to obtain recombinant adenovirus. The specific expression of target proteins by the recombinant adenovirus was verified by indirect immuno-fluorescence assay (IFA) with monoclonal antibodies against M and GP5.The results showed that the tandem linked M with GP5 could be co-expressed by adenovirus vector. Mice immunized with the constructed recombinant adenovirus induced strong humoral immunity (ELISA antibody and virus neutralizing antibody) and cellular immunity (lymphocyte proliferation and CTL responses). The results showed that the recombinant adenovirus has strong immunogenicity and provided the basis for the further experiments in pigs.
Adenoviridae ; genetics ; Animals ; Female ; Fluorescent Antibody Technique, Indirect ; Humans ; Mice ; NIH 3T3 Cells ; Plasmids ; Porcine respiratory and reproductive syndrome virus ; immunology ; Recombinant Fusion Proteins ; biosynthesis ; immunology ; Vaccines, Synthetic ; immunology ; Viral Envelope Proteins ; genetics ; immunology ; Viral Matrix Proteins ; genetics ; immunology ; Viral Vaccines ; immunology

BACKGROUNDTo clone the type common antigen gD of human herpes simplex virus I, II (HSV-I, II), the authors constructed recombinant expression vector Pmal-c2/gD and induced to express the fusion protein MBP-gD.

METHODSThe authors extracted HSV DNA,amplified gD gene by PCR assay and directly cloned it into prokaryotic expression vector pMAL-c2, then transformed it into E.coli DH5alpha. After proved to be correct by PCR, double enzyme digestion and sequencing, the fusion protein is induced to express by IPTG and detected by both Western blot and ELISA.

RESULTSThe constructed expression vector pMAL-c2/gD can be expressed with high efficiency. The product expressed was about 35.5% of the total bacterium proteins by SDS?PAGE analysis and was found nearly 39% as soluble protein,61% as inclusion in cytoplasm.

CONCLUSIONSThe authors constructed recombinant expression vector pMAL-c2/gD, the Western blotting result showed that the recombinant protein could be identified with gD specific monoclonal antibody DL6. Therefore the protein was of natural antigenic structure of gD.

Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Humans ; Plasmids ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; Viral Envelope Proteins ; biosynthesis ; genetics

Modified ORF5 (MORF5) and ORF6 gene of PRRSV were cloned into two multiple cloning sites of MVA transfer vector pLR-gpt to construct the recombinant plasmid pLR-MORF5/ORF6. Homologous recombination between pLR-MORF5/ORF6 and the wtMVA on BHK-21 cell line was mediated with liposome by infecting the cell with 0.01 MOI wtMVA two hours before transfecting the recombinant plasmid into the cell. When the cytopathic effect (CPE) was obvious, virus was collected from the cell plate and the recombinant virus was selected with drug selecting medium (2% MXHAT). After 12 cycles of selection, rMVA with a selection marker Eco gpt was obtained and named as rMVAgpt-MGP5/M. By infecting BHK-Cre expressing Cre recombinant enzyme, the Eco gpt marker in rMVAgpt-MGP5/M was deleted and this rMVA was named as rMVA-MGP5/M. The insertion of MORF5 and ORF6 into the MVA genome was confirmed with PCR analysis and the expression of MGP5 and M protein was identified with Western blot and IFA. Through biological study on the recombinant MVA, no obvious difference was observed between rMVA-MGP5/M and the wtMVA regarding to the CPE and growth curve. The recombinant MVA constructed in this study could coexpress the modified GP5 and M protein and the expressed product had good immunocompetence. Furthermore, the insertion of the MORF5 and ORF6 into MVA genome had no obvious effect on the replication and biological characteristics of this virus.
Animals ; Cell Line ; Genetic Vectors ; genetics ; Porcine Reproductive and Respiratory Syndrome ; prevention & control ; Porcine respiratory and reproductive syndrome virus ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Recombination, Genetic ; Swine ; Transfection ; Vaccines, DNA ; genetics ; immunology ; Vaccinia virus ; classification ; genetics ; metabolism ; Viral Envelope Proteins ; biosynthesis ; genetics ; Viral Matrix Proteins ; biosynthesis ; genetics

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.
Animals ; Antigens, Viral ; genetics ; immunology ; Artificial Gene Fusion ; Female ; Mice ; Mice, Inbred BALB C ; Porcine Reproductive and Respiratory Syndrome ; prevention & control ; Random Allocation ; Vaccines, DNA ; genetics ; immunology ; Viral Envelope Proteins ; genetics ; immunology ; Viral Structural Proteins ; genetics ; Viral Vaccines ; genetics ; immunology

In recent years, mass outbreaks of highly pathogenic (HP) porcine reproductive and respiratory syndrome virus (PRRSV) have spread all over the Chinese swine industry. Based on the first infectious cDNA clone of HP PRRSV strain pJX143 and that of an attenuated PRRSV, pAPRRS, constructed in our group, we constructed several chimeric clones with various substitutions of structural protein genes (ORF4-7) and 3' UTR between attenuated pAPRRS and virulent pJX143.Upon transfection of MA-104 cultured cells, all chimeric constructs pSX12, p5NX12, and p56N12 were rescued. The rescued viruses maintained the similar virological properties, based on the results of the growth curve of the rescued viruses. To test if the chimeric viruses can be used as a vaccine candidate, vSX12 and v56N12 vaccinated pigs were challenged with the HP PRRSV JX143 strain. As a result, the vSX12 vaccinated pigs were all seroconverted by 14-day-post vaccination, while v56N12 vaccinated pigs showed poor antibody response. Upon challenge, the vSX12-vaccinated group showed no signs of clinical PRRS syndrome, and virema period was shorten to 6 days post-challenge. Our results demonstrated that 1) vSX12 chimeric virus is a good vaccine candidate; 2) the virulence determinants of HP PRRSV probably located in coding regions other than ORF3-7 and 3' UTR, as our chimeric viruses were proved to be attenuated.
Animals ; Cloning, Molecular ; Open Reading Frames ; Porcine Reproductive and Respiratory Syndrome ; virology ; Porcine respiratory and reproductive syndrome virus ; genetics ; immunology ; Recombinant Fusion Proteins ; genetics ; immunology ; Recombination, Genetic ; genetics ; Swine ; Vaccines, Attenuated ; immunology ; Viral Envelope Proteins ; Viral Proteins ; biosynthesis ; genetics ; Viral Vaccines ; immunology