OBJECTIVETo prepare streptavidin-tagged hepatitis C virus (HCV) fusion protein and explore its application for the detection of antibody against HCV infection.

METHODSA recombinant plasmid pET-11d-C44P-SA was constructed, which coding a novel HCV diagnostic antigens (C44P) and streptavidin (SA) fusion protein, and the fusion protein was generated with BL21 (DE3) E Coli and identified by Western Blot analysis. Then the fusion protein was purified through the Ni-NTA affinity chromatography and over 90% purity has been achieved. Anti-HCV ELISAs were developed when the fusion protein was used in the biotin-pre-coated microplate or ordinary microplate, and then the sensitivity and specificity of the ELISA were evaluated with confirmed human sera panels.

RESULTSThe fusion protein was expressed in high yields and purified successfully, the ELISA detection of anti-HCV with human sera panel indicated that its sensitivity and specificity is higher when SA-tagged HCV antigen (C44P-SA) coated in biotin-pre-coated microplate, compared to C44P or C44P-SA coated in ordinary microplate.

CONCLUSIONThe sensitivity and specificity of anti-HCV ELISA can be improved when a novel HCV diagnostic antigen fused to SA combined with the biotin- pre-coated microplate. This study laid a foundation for improving the performance of HCV diagnostics.

Antibodies, Viral ; immunology ; Enzyme-Linked Immunosorbent Assay ; Hepatitis C Antigens ; genetics ; immunology ; metabolism ; Recombinant Proteins ; genetics ; immunology ; metabolism ; Streptavidin ; genetics ; immunology ; metabolism

OBJECTIVETo prepare eukaryotic expression of rotavirus (RV) SA11 capsid protein VP7, and to generate and purify yolk immunoglobulin (IgY) antibodies against the recombinant VP7 from Roman hens.

METHODSMA104 cells were infected with the standard SA11 strain and the culture fluid was collected. A DNA fragment of 978 bp encoding SA11 VP7 was obtained by RT-PCR amplification from genomic RNA of RV SA11. The PCR products were ligated to pMD18-T vector following the confirmation by DNA sequencing and sub-cloned into pPICZalphaB. The recombinant pPICZalphaB-SA11 VP7 was transformed into E coli Top10. The plasmids were linearized by digestion of BstXI and transformed into Pichia pastoris X-33 through electroporation by DNA sequencing. The transformants were induced with methanol for expression. The cultural supernatant was subjected to SDS-PAGE and Western blotting. Fusion expression was purified through the column of affinity chromatography. IgY was identified and purified by SDS-PAGE and Western blotting from eggs of Roman hens immunized with recombinant SA11 VP7.

RESULTSThe RNA extracted from the RV culture fluid consisted of 11 bands visualized by silver staining. The expression vector pPICZalphaB-SA11 VP7 was constructed and the fusion protein in Pichia pastoris X-33 was harvested and purified. The recombinant SA11 VP7 with molecular weight of 40 200 was identified by Western blotting. The IgY antibodies against the recombinant SA11 VP7 were produced with a purity of 95 percent and yield of 10.2 mg per egg.

CONCLUSIONThe preparation of IgY antibodies to recombinant SA11 VP7 might lay a foundation for the development of vaccines and diagnostic techniques.

Animals ; Antigens, Viral ; genetics ; immunology ; metabolism ; Capsid Proteins ; genetics ; immunology ; metabolism ; Chickens ; Cloning, Molecular ; Immunoglobulins ; immunology ; isolation & purification ; Recombinant Proteins ; genetics ; immunology ; metabolism

Taking the genome DNA of Infectious Bovine Rhinotracheitis Virus (IBRV) as the template, the gG gene was amplified with PCR and cloned into the T cloning vector pMD18-T. After being identified by restriction digestion and DNA sequencing, the insert was subcloned into the expression vector pGEX-KG. Sodium docecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot assay showed that this gene was expressed as both soluble form and inclusion body by the transformed E. coli BL21 strain (DE3). The fusion protein was purified and used as the coating antigen to develop the indirect Enzyme-Linked Immunosorbent Assay (ELISA). Comparison between this gG-ELISA and commercial IBRV gB-ELISA Kit (IDEXX) was made in the detection of 380 cow serum samples. The results demonstrated an agreement of 92%. By using this novel gG-ELISA, 1248 cow serum samples were tested and the average positive rate of IBRV antibodies for imported cows is 21.7%, while the positive rate ranged greatly from 0.0%-41.5% for Hubei local Chinese Black and White Dairy Cows.
Animals ; Antibodies, Viral ; blood ; immunology ; Antigens, Viral ; genetics ; immunology ; Cattle ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay ; methods ; Escherichia coli ; genetics ; metabolism ; Female ; Herpesvirus 1, Bovine ; genetics ; immunology ; Male ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Sensitivity and Specificity ; Viral Proteins ; biosynthesis ; genetics ; immunology

Human metapneumovirus (hMPV) is a recently identified respiratory virus more like human respiratory syncytial virus in clinical symptoms. Matrix protein (M) is one of the most important structural proteins. For further studying of hMPV, the full length of M genes from the recombinant plasmid pUCm-M1816 and pUCmM1817 were cloned by PCR and sub-cloned into the pET30a(+) vector, which is a prokaryotic expression vector, after dual-enzyme digestion with Bam HI and Xho I. The positive recombinated plasmids were transformed into E. coli BL21 (DE3) and expressed under the inducing of IPTG. Target proteins were characterized by SDS-PAGE and Western blotting. In this article, we' ve successfully constructed the recombinated plasmids pET30a-M1816 and pET30a-M1817 which have correct open reading frames confirmed by dual-enzyme digestion analysis and sequencing. The fusion proteins with 6 x His-N were highly produced after inducing by 1mmol/ L IPTG at 37 degrees C. A unique protein band with approximate 27.6 kD was characterized by SDS-PAGE. Most of the target protein existed in inclusion body. Western blot analysis showed that the target protein has specific binding reaction to rabbit antiserum against polypeptides of the matrix protein of hMPV. So the M genes were highly expressed in the prokaryotic system and the expressed M proteins have specific antigenic activities. It can be used for further studying of hMPV infections in Beijing.
Animals ; Antigens, Viral ; genetics ; immunology ; metabolism ; Blotting, Western ; China ; Gene Expression ; Genetic Vectors ; genetics ; Humans ; Immune Sera ; immunology ; Metapneumovirus ; genetics ; immunology ; metabolism ; Plasmids ; genetics ; Prokaryotic Cells ; metabolism ; Rabbits ; Species Specificity ; Viral Structural Proteins ; genetics ; immunology ; metabolism

Cytomegalovirus (CMV) infection is a dangerous complication in patients with chronic graft versus host disease (cGVHD). CMV-specific immunity depends on the activity of T cells. This study was aimed to investigate the effect of CMV pp65 gene modified dendritic cells (DCs) on activation of autologous T cells. Lentivirus system was utilized to introduce the CMV full-length pp65 gene into mouse DCs; CpG-DNA was used to induce mature DCs; flow cytometry and immunofluorescence were used to determine the expression of antigen and IFNgamma in T lymphocytes. The results showed that the DCs were infected with lentivirus at a multiplicity of infection (MOI) of 50 with optimal infectious efficiency of 30%-40%; mature DCs expressing pp65 gene could stimulate autologous naive T cells to express CD69 specifically; mature DCs expressing PP65 could stimulate autologous CD4+ or CD8+ T cells to produce IFNgamma. It is concluded that CMV pp65-modified and CpG-DNA-induced mature DCs can activate CMV-specific T lymphocytes in vitro.
Animals ; Antigens, CD ; genetics ; metabolism ; Antigens, Differentiation, T-Lymphocyte ; genetics ; metabolism ; Antigens, Viral ; immunology ; CD4-Positive T-Lymphocytes ; immunology ; CD8-Positive T-Lymphocytes ; immunology ; CpG Islands ; genetics ; Cytomegalovirus ; immunology ; DNA ; genetics ; Dendritic Cells ; cytology ; immunology ; metabolism ; Humans ; Interferon-gamma ; genetics ; metabolism ; Lectins, C-Type ; Lentivirus ; genetics ; metabolism ; Mice ; Phosphoproteins ; genetics ; metabolism ; Viral Matrix Proteins ; genetics ; metabolism

Antigens, Viral ; metabolism ; China ; epidemiology ; Humans ; Influenza B virus ; classification ; genetics ; immunology ; Phylogeny

OBJECTIVETo prepare anti-recombinant protein antibody from immunized mice with recombinant nucleocapsid protein (NP) of human influenza A3 (IFV-A3) virus expressed in prokaryotic cell, and to explore the feasibility of utilizing anti-recombinant protein antibody to detect influenza A virus.

METHODSNP genes of human influenza A virus were analyzed with computer softwares of ClustalX, Antheprot, et al. to determine the antigenicity in conserved regions. Three different partial NP genes were harvested and cloned into pET-28(c) plasmid, the recombinant plasmids were induced to express partial NP segments in BL21 cells. The recombinant proteins were purified with Ni-agarose by affinity chromatography and immunized BALB/c mice. The polyclonal antisera harvested from mice were analyzed with Western Blot and immunohistochemistry assays to detect the reactions with IFV-A.

RESULTSThree recombinant plasmids were expressed with high yield in BL21 cells, about 15-20 mg/L. Western Blot results indicated that the three prepared antisera (1:2000) positively reacted with NP from IFV-A3-infected cells. And immunohistochemistry assays suggested that anti-NP1, anti-NP2, anti-NP3 antisera positively reacted with IFV-A3 or IFV-A1-infected MDCK cells, with titers of 1:640 to 1:1280.

CONCLUSIONThe recombinant NP of IFV-A3 would induce polyclonal antibodies with high titers in mice. The polyclonal antibodies would cross-react with IFV-A3 and IFV-A1. It is feasible to predict the antigenicity with systematical bioinformatics analyses and then induce anti-IFV antibodies with high dilutions, and it is possible to be utilized in the early detection and subtyping analyses of IFV-infections.

Animals ; Antibodies, Viral ; blood ; Antigens, Viral ; genetics ; immunology ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; Humans ; Influenza A virus ; genetics ; immunology ; Influenza, Human ; immunology ; virology ; Male ; Mice ; Mice, Inbred BALB C ; Nucleocapsid Proteins ; genetics ; immunology ; Recombinant Proteins ; genetics ; immunology

Classical swine fever virus (CSFV), an enveloped positive-stranded RNA virus in the genus Pestivirus of the Flaviviridae family, is the causative agent of a highly contagious swine disease characterized by symptoms of hemorrhagic fever and immune depression, usually leading to substantial economic losses. The serological methods for detection of CSFV antibody such as ELISA are important means for the diagnosis of CSFV and immune surveillance. It is difficult to obtain CSFV antigen with high quality using traditional method because its titration titer is low in cell culture. CSFV has four structural protein named C, E0, El and E2. The E2 protein contains major antigenic determinants that are conserved between different CSFV strains and involved in neutralization by antibodies. So recombinant E2 protein can be developed as an alternative to the intact viral antigen. So far, CSFV E2 have not been expressed in E. coli with high level. Many factors, such as the secondary structure, the stability of 5' and 3' terminus of gene, the location of SD sequence and the bias of codes, are involved in the expressing level of foreign gene in E. coli . In this study, two sites of the E2 gene sequence were confirmed to be detrimental to its expression efficiency in E. coli through the computer-aided analysis. So they were mutated using recombinant PCR without changing the amino acids sequence of CSFV E2 gene. A plasmid was constructed by inserting the mutated E2 gene into the prokaryotic expression vector pET-28a(+) and named pETE2. The E. coli competent host BL21 (DE3)lysS transformed with pETE2 could express the E2 gene at high level, amounting to 28% of the total protein of the induced recombinant bacteria at the presence of IPTG. Except the hydrophobic transmembrane domain at C terminus, the recombinant E2 protein includes the total aa sequence. So it contains all the potential linear antigen epitopes of E2 protein because hydrophobic aa region can not form epitope. The recombinant E2 protein was CSFV-specific as proved by Western blotting and indirect ELISA. The rabbits immunized with the recombinant E2 can be protect from the challenge of hog cholera lapinized virus. This is the first report that E2 gene is expressed with high level expression in E. coli. In conclusion, it is an effective measure that mutate the CSFV E2 gene to increase its expression level in E. coli. The recombinant CSFV E2 protein possess fine immunonicity and can be used the antigen for the detection of CSFV antibody.
Antigens, Viral ; genetics ; immunology ; metabolism ; Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; genetics ; metabolism ; Mutagenesis, Site-Directed ; methods ; Polymerase Chain Reaction ; Recombinant Proteins ; genetics ; immunology ; metabolism ; Viral Envelope Proteins ; genetics ; immunology ; metabolism

OBJECTIVETo evaluate in vivo immunological protective efficacy and safety of expressed recombinant rotavirus epitopes in mice.

METHODSUsing the Flock House virus capsid protein as a vector, three epitopes derived from rotavirus Vp4 amino acid 223-242 [rotavirus epitope A, (REA)], 243-262 [rotavirus epitope B, (REB)], and 234-251 [rotavirus epitope C, (REC)] were genetically engineered on the surface of the vector protein and expressed in pET-3 (E. coli BL21 [DE3]) system into multiple epitopes, REABC, which comprises REA, REB, and REC. Kunming strain mice were inoculated with the recombinant epitopes REABC, and then challenged perorally by cell culture-adapted rotavirus Wa (type G1P1A) and SA11 (type G3P2). Infection syndrome was observed, and virus antigen in stools of mice and serum neutralizing antibody activities were determined and analyzed.

RESULTSThe recombinant epitopes REABC significantly induced rotavirus specific neutralyzing antibodies against WA and SA11, reduced virus reproduction, elicitted immune memory in inoculated mice, and protected inoculated mice from challenge by WA or SA11 (P<0.001).

CONCLUSIONThe recombinant epitopes have high immunological protective efficacy and mild side effects in mice. It may be used as an epitope-based vaccine candidate in human.

Animals ; Antigens, Viral ; immunology ; Capsid ; immunology ; metabolism ; Capsid Proteins ; immunology ; Epitopes ; biosynthesis ; immunology ; Escherichia coli ; genetics ; Female ; Genetic Vectors ; Male ; Mice ; Random Allocation ; Recombinant Proteins ; biosynthesis ; immunology ; Rotavirus ; immunology ; Rotavirus Infections ; immunology ; prevention & control ; Viral Vaccines ; immunology

In order to increase the expression level of target gene and to simplify the purifying process of separation and purification, we performed the transgenetic research of antigen VP7 gene into peanut via Agrobacterium tumefaciens. The plant binary expression vector is pBOG3VP7 harboring fusion gene oleosin-vp7, which is promoted by ole-promoter. Cotyledon nodes were used as transformation recipients. Transformed individuals were obtained through selection on medium containing 125 mg L-1 Kan. Integration of transgenes was assessed by PCR amplification and PCR-Southern blot hybridization. Taking pBOG3VP7 plasmid as positive control, non-transformed peanut as negative control. 6 plants among 11 plants grown up through seletion medium were detected by PCR and the rate of positive plants is 54.5%. PCR positive plants were further analysed by PCR-Southern blot hybridization. The results showed that 3 plants have DNA bloting bands. The results also showed that the foreign gene was integrated into genome of transformed peanuts. Elevated expression of rotavirus VP7 antigen in transgenic peanuts was a critical factor in the development of efficient and cheap plant oral vaccine.
Agrobacterium tumefaciens ; genetics ; Antigens, Viral ; biosynthesis ; genetics ; Arachis ; genetics ; metabolism ; Capsid Proteins ; biosynthesis ; genetics ; Plants, Genetically Modified ; genetics ; metabolism ; Rotavirus ; genetics ; immunology ; Transformation, Genetic ; Vaccines, Synthetic