Escherichia coli ; genetics ; Humans ; Recombinant Fusion Proteins ; immunology ; Viral Nonstructural Proteins ; genetics ; immunology

Two Heptad repeat motifs (HR1 and HR2) from paramyxoviruses F protein could form thermostable heterodimers containing high alpha-helix while virus infected host cell. Following that the viral membrane and the host cell membrane were juxtaposed, which leads to membrane fusion. Mumps virus (MuV) is a member of the genus Rubulavirus in the family of Paramyxoviridae. MuV could use similar infection mechanism as well as other paramyxoviruses. In this study the HR1 and HR2 regions of MuV F protein were predicted by a computer program and expressed in E. coli with the GST fusion expression system. The GST fusion or GST-removed proteins were purified with Gluthathion Sepharose 4B Column. GST pull-down experiment suggested the interaction of HR1 and HR2 peptides, and analysis of gel filtration showed two peptides could form multimer, which indicates that the HR regions of MuV F protein may play an important role in virus fusion.
Membrane Fusion ; genetics ; Mumps virus ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; chemistry ; genetics ; isolation & purification ; Repetitive Sequences, Amino Acid ; Viral Fusion Proteins ; biosynthesis ; genetics ; isolation & purification

Cloning, Molecular ; Escherichia coli ; genetics ; Hepacivirus ; genetics ; Humans ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Viral Nonstructural Proteins ; biosynthesis ; genetics ; immunology

BACKGROUNDTo obtain thermal stable, soluble, biologically active hepatitis E virus recombinant antigen using thioredoxin fusion expression system.

METHODSHEV ORF2 gene fragment (6964-7126 nt) was inserted into thioredoxin fusion expression vector pThioHisA. The recombinant plasmid was transformed into E. coli BL21 strain. After induction with IPTG, cells were lysed and the supernatant was subjected to 80 degree treatment for 10 minutes. After centrifugation, the supernatant was tested by ELISA.

RESULTSSDS-PAGE analysis showed the thioredoxin. HEV fusion protein was highly expressed and was thermally stable, soluble. HEV specific ELISA confirmed this fusion protein possessing HEV specific antigenicity.

CONCLUSIONSUsing thioredoxin fusion expression system, a soluble, thermal stable, biologically active HEV recombinant antigen was successfully expressed.

Antigens, Viral ; biosynthesis ; genetics ; Gene Expression ; Genetic Vectors ; Hepatitis E virus ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Thioredoxins ; genetics ; Viral Proteins ; biosynthesis ; genetics

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

In order to achieve large-scale production of HSV-IgM (HSV1, HSV2) human-mouse chimeric antibody in vitro, the gene sequence of the corresponding hybridoma cell was harvested by RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) technique to clone the chimeric antibody into eukaryotic expression vectors, and express the target proteins in CHO-S cells. At the same time, the screening process of stable cell lines was optimized, and the pressure conditions of pool construction stage and monoclonal screening stage were explored. Finally, the target protein was purified by protein L affinity purification method and the biological activity was detected. The recombinant IgM antibodies, HSV1 and HSV2, weighted at 899 kDa and 909 kDa respectively, were prepared. The optimal screening pressure was 20P200M (the first phase of pressure) and 50P1000M (the second phase of pressure). The final titer for the monoclonal expression of HSV1-IgM and HSV2-IgM was 1 620 mg/L and 623 mg/L, respectively. This study may facilitate the development of quality control products of HSV1 and HSV2 IgM series recombinant antibodies as well as efficient expression of IgM subtype antibodies in vitro.
Cricetinae ; Humans ; Animals ; Mice ; Immunoglobulin M/genetics* ; Antibodies, Viral ; CHO Cells ; Cricetulus ; Hybridomas ; Recombinant Fusion Proteins

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

Herpesviridae is a large family comprising linear, double-stranded DNA viruses. Herpesviridae contains three subfamilies: α-, β- and γ-herpesviruses. The glycoproteins gB, gH and gL of each subfamily form the "core fusion function" in cell-cell fusion. Other herpesviruses also need additional glycoproteins to promote fusion, such as gD of the Herpes simplex virus, gp42 of the Epstein-Barr virus, and gO or UL128-131 of the Human cytomegalovirus. In contrast, glycoproteins gM or gM/gN of herpesvirus inhibit fusion. We describe the molecular mechanisms of glycoprotein-induced fusion and entry of herpesviruses. It will be helpful to further study the pathogenic mechanism of herpesvirus.
Animals ; Cell Fusion ; Glycoproteins ; genetics ; metabolism ; Herpesviridae ; genetics ; metabolism ; Herpesviridae Infections ; physiopathology ; virology ; Humans ; Viral Proteins ; genetics ; metabolism

To construct plasmid of recombinant protein candidate vaccine of respiratory syncytial virus, express it in E. coli, and to investigate its immunogenicity and protective efficacy. A CD8+ T cell epitope from respiratory syncytial virus (RSV) M2 protein F/M2:81 - 95 and the G:125-225 (G1) gene fragments from RSV-G protein containing B cell epitopes were amplified by PCR method and then inserted into the prokaryotic expression vector pET-DsbA after bonding to a linker. The fusion protein DsbA-G1-Linker-F/M2:81-95 (D-G1LF/M2) was expressed successfully in E. coli BL21 (DE3). The product was proved to be RSV-specific by Western-blot. After purified by affinity chromatography on Ni+ Sepharose and renatured by gradient dialysis. D-G1LF/M2 was used to immune BALB/c mice. D-G1LF/M2 induced high anti-D-G1LF/M2 IgG, anti-RSV IgG and neutralizing antibody titers in serum and lung of BALB/c mice, and elicied RSV-specific CTL responses. The IgG subclass distribution revealed that IgG1/IgG2a ratio was 2.66. Viral titration indicated that D-G1LF/M2 could protect BALB/c mice against RSV challenge in lung.
Animals ; Antibodies, Viral ; blood ; immunology ; Escherichia coli ; genetics ; metabolism ; Humans ; Immunoglobulin G ; blood ; immunology ; Mice ; Mice, Inbred BALB C ; Plasmids ; genetics ; immunology ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Respiratory Syncytial Virus Infections ; prevention & control ; Respiratory Syncytial Virus Vaccines ; biosynthesis ; genetics ; immunology ; Respiratory Syncytial Virus, Human ; genetics ; immunology ; Viral Envelope Proteins ; genetics ; Viral Fusion Proteins ; genetics ; Viral Proteins ; genetics

LTB gene fragment was amplified by PCR from plasmid pMDTLT, and a recombinant plasmid pETLTBVP1 was constructed by inserting LTB gene fragment into VP1 gene expression plasmid pETVP1 constructed previously. The recombinant plasmids were transformed into E. coli BL21(DE3) and induced to express by IPTG. The recombinant protein existed in the inclusion body and its molecular weight was about 39 kD proved by SDS-PAGE analysis. Western blotting showed that the fusion protein could be reacted with both anti-FMDV and anti-cholera toxin serum demonstrating the immunoactivity of the fusion protein. Strong immune responses can be induced in mice inoculated with the fusion protein intraperitoneally, and the serum antibody level is higher than that of commercial foot-and-mouth disease vaccines.
Animals ; Antibodies, Viral ; blood ; Bacterial Toxins ; genetics ; immunology ; metabolism ; Capsid Proteins ; genetics ; immunology ; metabolism ; Enterotoxins ; genetics ; immunology ; metabolism ; Escherichia coli ; genetics ; metabolism ; Escherichia coli Proteins ; Female ; Gene Fusion ; genetics ; Mice ; Plasmids ; genetics ; Recombinant Fusion Proteins ; genetics ; immunology ; metabolism