Hepatitis C virus (HCV) is an important human pathogen that causes chronic liver disease worldwide. It is desirable to develop vaccines to prevent HCV infection, or at least to prevent progression to chronicity. We once constructed an optimized hepatitis C virus core and envelope 2 fusion antigen DNA vaccine, which could induce humoral and cellular immune responses against HCV core and E2 protein in BALB/c mice efficiently. Flt3 (Fms-like tyrosine kinase 3) -ligand has been identified as an important cytokine for the generation of professional antigen-presenting cells, particularly dendritic cells. We reasoned that a DNA vaccine coexpressing the antigen and FL may activate immune responses more effectually. In this study, The influence of FL on this HCV DNA vaccine was evaluated. The cDNA encoding signal peptide and extracellular domain of murine FL was inserted into the plasmid pST-CE2t, and the resulting plasmid pST-CE2t/FL was transfected into COS7 cells. The HCV core and E2 protein were detected by Western blotting, and the soluble murine FL was detected by ELISA. Eight-week-old female BALB/c mice were inoculated intramuscularly with 100 microg pST-CE2t, pST-CE2t/FL or mock vector, respectively, and boosted at the same dosage 3 weeks later. Anti-HCV core and E2 total IgG and isotypes were measured at weeks 1,3,5,7. Splenocyte proliferative response to recombinant HCV core and E2 protrein were detected at week 7. SP2/0 cells expressing HCV core protein were used as target cells for the detection of cytotoxic T lymphocyte (CTL) response. Western blot analysis showed that a protein band with molecular weight about 70 kD from lysate of COS7 cells transfected with plasmid pST-CE2t/FL could be detected by anti-HCV core or E2 monoclonal antibodies, which indicated that pST-CE2t could express glucosylated HCV core and E2 fusion protein. Murine FL could be detected in the culture supernatant of COS7 cells transfected with pST-CE2t/FL. Plasmid pST-CE2t immunized mice developed higher anti-HCV core and E2 IgG seroconversion rates and titers than pST-CE2t/FL group did at different various times, but the IgG2a/IgG1 ratio of anti-HCV E2 protein in pST-CE2t/FL group is much higher than pST-CE2t group. Splenocytes from pST-CE2t or pST-CE2t/FL immunized mice could proliferate with stimulation of HCV core or E2 protein in vitro, although pST-CE2t/FL group showed much stronger response. Splenocytes from mice immunized with pST-CE2t/FL induced 79.03% +/- 9.95% of target cell lysis at the effector/target ratio of 100:1, which was significantly greater than the lysis (62.2% +/- 8.62%) observed in mice immunized with pST-CE2t. Our data demonstrated that the incorporation of FL can preferentially enhance the cellular response to this HCV fusion antigen DNA vaccine. In contrast, HCV specific antibodies were inhibited by FL in vaccinated mice. More and more data supports that recovery from acute HCV infection may depend upon the generation of broad-based cellular immune responses to viral proteins. So, FL may be of potential value as an adjuvant in the development of DNA-based immunization for prophylactic and therapeutic vaccine against HCV infection.
Animals ; Blotting, Western ; COS Cells ; Cell Line ; Cercopithecus aethiops ; Enzyme-Linked Immunosorbent Assay ; Female ; Hepatitis C Antigens ; genetics ; immunology ; metabolism ; Membrane Proteins ; genetics ; physiology ; Mice ; Mice, Inbred BALB C ; Vaccines, DNA ; genetics ; immunology ; Viral Core Proteins ; genetics ; immunology ; metabolism ; Viral Envelope Proteins ; genetics ; immunology ; metabolism ; Viral Fusion Proteins ; genetics ; immunology ; metabolism

BACKGROUNDTo observe the features of serum specific IgA, IgG, IgM antibodies in the acute phase of hemorrhagic fever renal syndrome (HFRS).

METHODSThe nucleocapsid (NP) protein and glycoproteins (GP) of Hantavirus were expressed by recombinant baculovirus, and used as ELISA antigens to test 61 serial sera of 14 acute phase HFRS patients.

RESULTSSeoul like virus RNA were detected from 11 of 14 patients. An early and strong IgA, IgG and IgM antibody response to recombinant NP (rNP) was observed in almost all HFRS cases. The titers of antibody to rNP was apparently higher than that to Rgp. In the early stage, titer of IgG antibody elevated most drastically among all the three classes of antibodies to rNP, followed by IgM and IgA antibody responses. The elevation trend of IgM and IgA antibodies to rNP stayed nearly at the same level, but the IgA titers to rNP were apparently higher than that of IgM. Among the antibodies to rGP, IgA changed distinctly greater than IgG. The elevation trend of IgM could be found during first week after the onset, and the titers dropped gradually after the second week. IgM antibodies of one case who was viral RNA positive were not detected at early stage, but IgA titers were high. The only severe case of the 14 patients kept the lower IgA, IgG and IgM during the whole acute phase.

CONCLUSIONHFRS patients kept an early and strong humoral response to NP and GPs in acute phase of HFRS.IgA could be used together with IgM to improve the diagnostic accuracy.

Acute Disease ; Adult ; Antibodies, Viral ; blood ; Capsid Proteins ; genetics ; immunology ; Female ; Hantavirus ; genetics ; immunology ; Hemorrhagic Fever with Renal Syndrome ; immunology ; virology ; Humans ; Immunoglobulin Isotypes ; blood ; Male ; Viral Core Proteins ; genetics ; immunology ; Viral Envelope Proteins ; genetics ; immunology

OBJECTIVESTo construct and screen a primarily phage display library of HCV C and E1 genes evolved with an artificial pattern.

METHODSTwo genes of about 1 kb with different genotypes were evolved by DNA shuffling. The re-assembled HCV C and E1 genes were cloned into a phage vector. After being rescued with helper phage M13KO7, a phage display library was constructed. Then the library was screened with anti-C and E1 McAb. Double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was carried out on twenty individual phage clones selected randomly to detect their binding and reactive activity with high-titer HCV-positive sera. Normal sera were used as controls.

RESULTSThe phage display library of HCV C and E1 genes which evolved with an artificial pattern was constructed. Their capacity amounted to 1.64 x 10(6), and 86 percent of the clones contained C and E1 genes. After four rounds of panning, the phage library was specifically enriched. Twelve positive clones were successfully screened.

CONCLUSIONThe capacity and diversity of the constructed library are enough for screening. The results demonstrate the superiority of the specific binding and reactive activity and affinity of the 12 phage clones from the HCV positive sera.

DNA, Viral ; genetics ; Gene Library ; Hepacivirus ; genetics ; Peptide Library ; Viral Core Proteins ; genetics ; Viral Envelope Proteins ; genetics

Rubella virus (RV), one of pathogens in TORCH syndrome, can lead to anisotropy of the fetus, and therefore it is of great significance to screen RV infection among women at child-bearing age. At the present, the screening of RV infection is mainly based on the ELISA method, the specificity of RV antigens is very important for ELISA tests. The antigenicity of RV is closely associated with its structural proteins, including capsid protein C, and envelope glycoproteins E1 and E2, which are important surface antigens of RV. This paper reviews the advances in the studies on the structure features, immunogenicity and recombinant proteins of the three structural proteins.
Antibodies, Viral ; analysis ; Enzyme-Linked Immunosorbent Assay ; Recombinant Proteins ; immunology ; Rubella virus ; genetics ; immunology ; Viral Core Proteins ; genetics ; immunology ; Viral Envelope Proteins ; genetics ; immunology ; Viral Structural Proteins ; genetics ; immunology

BACKGROUNDTo develop HPV16 L1/E6 and L1/E7 prophylactic and therapeutic DNA vaccines.

METHODSThe nucleotides within HPV 16 E6 and E7 genes, which are responsible for viral transforming activity, were mutated by mega primer site-directed mutagenesis method. The correctly mutated E6 and E7 fragments were separately cloned into an eukaryotic expression vector pVAX1, together with HPV 16 L1 gene, generating chimeric recombinants plasmids 1MpVAX1-L1E6, 2MpVAX1-L1E6, 1MpVAX1-L1E7, 2MpVAX1-L1E7 and 3MpVAX1-L1E7. CHO cells were transiently transfected with the individual DNA vaccines by calcium phosphate method. Target protein expressions in the extracts of the transfected cell lines were measured by ELISA and immunohistochemistry, with HPV 16 L1 and E6 specific monoclonal antibodies.

RESULTSELISA showed the P/N ratios in the cell extracts transfected with L1E6 and L1E7 plasmids were greater than 2.1. Immunohistochemistry revealed brownish precipitant signal in cytoplasm and nuclei of the transfected cells.

CONCLUSIONSSuccessful constructions of prophylactic and therapeutic DNA vaccine plasmids may be useful for future animal experiment and clinical trial.

Animals ; CHO Cells ; Capsid Proteins ; Cricetinae ; Cricetulus ; Enzyme-Linked Immunosorbent Assay ; Humans ; Mutagenesis, Site-Directed ; Oncogene Proteins, Fusion ; biosynthesis ; immunology ; Oncogene Proteins, Viral ; biosynthesis ; genetics ; immunology ; Papillomaviridae ; genetics ; Papillomavirus E7 Proteins ; Plasmids ; genetics ; Point Mutation ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Repressor Proteins ; Transfection ; Vaccines, DNA ; biosynthesis ; genetics ; Viral Vaccines ; biosynthesis ; genetics

HPV16 L2E7 is a fusion protein used for therapeutical vaccine targeting HPV virus. To increase its expression in Escherichia coli, we optimized the codon usage of HPV16 l2e7 gene based on its codon usage bias. The optimized gene of HPV16 sl2e7 was cloned into three different vectors: pGEX-5X-1, pQE30, ET41a, and expressed in JM109, JM109 (DE3) and BL21 (DE3) lines separately. A high expression line was selected with pET41a vector in BL21 (DE3) cells. After optimization of the growth condition, including inoculation amount, IPTG concentration, induction time and temperature, the expression level of HPV16 L2E7 was increased from less than 10% to about 28% of total protein. HPV16 L2E7 protein was then purified from 15 L culture by means of SP Sepharose Fast Flow, Q Sepharose Fast Flow and Superdex 200 pg. After renaturing, HPV16 L2E7 protein with ≥ 95% purity was achieved, which was confirmed via SDS-PAGE gel and Western blotting. The combined use of purified HPV16 L2E7 and CpG helper has shown clear inhibition of tumor growth in mice injected with tumor cells, with six out of eight mice shown no sign of tumor. This study lays a solid foundation for a new pipeline of large-scale vaccine production.
Animals ; Capsid Proteins ; biosynthesis ; Codon ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; Genetic Vectors ; Human papillomavirus 16 ; Mice ; Neoplasms, Experimental ; prevention & control ; Oncogene Proteins, Viral ; biosynthesis ; Papillomavirus E7 Proteins ; biosynthesis ; Papillomavirus Vaccines ; therapeutic use ; Recombinant Fusion Proteins ; biosynthesis

OBJECTIVETo develop a best method of constructing influenza NP fusion gene containing enhanced green fluorescent protein (EGFP).

METHODSThe full-length NP gene of influenza A was amplified by RT-PCR and was inserted into an eukaryotic expression vector pEGFP-N1 in order to construct a fusion gene of pEGFP-N1-NP using three different methods. Method one, NP gene containing restriction endonucleases and pEGFP-N1 were both digested using the same restrict enzymes and ligated, yielding the fusion gene of pEGFP-N1-NP. Method two, NP gene was cloned into pMD19-T Vector to construct a plasmid of pMD19-T-NP. The pMD19-T-NP cloned into pEGFP-N1 to construct the fusion gene of pEGFP-N1-NP; Method three, NP gene containing restriction endonucleases was cloned into pMD19-T Simple Vector to construct a plasmid of pMD19-T-NP. The pMD19-T-NP cloned into pEGFP-N1 to construct the fusion gene of pEGFP-N1-NP.

RESULTSThe fusion gene of recombinant eukaryotic expression vector pEGFP-N1-NP was successfully constructed by using method three.

CONCLUSIONSThe full-length NP gene is obtained and its fusion gene of recombinant eukaryotic expression plasmid is successfully constructed. This study provides foundation for further understanding the biological function of NP protein and the mechanism of diseases induced by influenza A virus.

Artificial Gene Fusion ; Cloning, Molecular ; Genetic Vectors ; Green Fluorescent Proteins ; genetics ; Polymerase Chain Reaction ; RNA-Binding Proteins ; genetics ; Viral Core Proteins ; 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

OBJECTIVETo examine the antigenicity of hepatitis C virus (HCV) F protein and investigate serum prevalence of anti-F in HCV-infected patients.

METHODSEleven pairs of overlapping primers were used to synthesize the full-length HCV f gene, from which the truncated HCV f65 gene fragment was amplified by PCR. HCV f65 gene was then cloned into pET32a(+), and transformed into E. coli strain Plyss (DE3). This recombinant E.coli was induced by IPTG for the production of HCV F65 protein. The expressed HCV F65 protein, purified by Ni-NTA agarose, was further used in ELISA to detect serum anti-F, and to immunize rabbits for making polyclonal anti-F. The rabbit polyclonal anti-F was purified by Staphylococcus aureus protein A agarose.

RESULTSAfter recombinant pET32a(+)-f65 was constructed successfully, HCV F65 protein was expressed and purified. The purified HCV F65 protein was used as a capture antigen in ELISA to detect serum anti-F in HCV infected patients (n = 30). The result showed that the mean A450 value and the positive rate of serum anti-F were 0.125+/-0.061 and 63.3%, respectively. The rabbit-derived polyclonal anti-F reacted specifically with HCV F65 protein, of which the titer was 1:30,000.

CONCLUSIONOur expressed HCV F65 protein is of antigenicity, and can be used to determine serum anti-F. Anti-F IgG does exist in the sera of the HCV-infected patients. Moreover, the rabbit-derived polyclonal anti-F can be used to detect HCV F protein.

Animals ; Antibodies, Viral ; blood ; Hepacivirus ; genetics ; immunology ; Hepatitis C ; blood ; epidemiology ; immunology ; Hepatitis C Antigens ; blood ; immunology ; Humans ; Prevalence ; Rabbits ; Viral Core Proteins ; blood ; immunology ; Viral Envelope Proteins ; immunology

OBJECTIVETo investigate the variations of HCV core and E2 region epitopes during transfusion of activated immune cells.

METHODSFour patients receiving transfusion of activated immune cells were under continuously observation. HCV titers were measured by quantitive PCR. HCV core and E2 regions were cloned and sequences were analyzed by computer software.

RESULTSDuring the follow-up the serum ALT levels and the HCV virus titers fluctuated greatly in each of these persons. After transfusion, no significant variations were observed in HCV core and E2 coding regions.

CONCLUSIONSThe alteration of host immune attacks could induce the fluctuations of HCV load without any mutations in the currently observed coding genes of the epitopes.

Adult ; Aged ; Alanine Transaminase ; blood ; Epitopes ; genetics ; Female ; Genetic Variation ; Hepacivirus ; genetics ; Hepatitis C, Chronic ; blood ; therapy ; virology ; Humans ; Immunotherapy ; Male ; Middle Aged ; Viral Core Proteins ; genetics ; Viral Envelope Proteins ; genetics ; Viral Load