OBJECTIVETo construct the virus-like parcel expressing hepatitis B virus (HBV) C gene and identify its immunogenicity.

METHODSHBV C gene was cloned into the shuttle vector pSC11, and the resulted plasmid pSC11-C was transfected into modified vaccinia virus Ankara (MVA).

RESULTSpSC11-C was correctly constructed as verified by sequence analysis and PCR, and the recombinant virus-like parcel possessed good immunogenicity.

CONCLUSIONThe MVA-C expressing HBV C gene has been successfully constructed to provide important basis for gene therapy research of chronic HBV infection.

Genes, Viral ; Genetic Vectors ; Hepatitis B Core Antigens ; genetics ; Recombination, Genetic ; Vaccinia virus ; genetics

OBJECTIVETo screen enhancer-like sequences from vaccinia virus genome, to construct an expression vector harboring prokaryotic enhancer-like sequence and study the effect of interferon gene expression.

METHODSEnhancer-like element from vaccinia virus genome was obtained by using the chloramphenicol acetyl-transferase cat gene as reporter gene. An expression vector harboring prokaryotic enhancer-like sequence VV1 from vaccinia virus was constructed. Interferon was expressed and assayed.

RESULTSEighteen enhancing sequences were found. From them two enhancer-like sequences with distance and orientation independence property were screened and named VV1 and VV16 respectively. Quantification test showed that the direct and reverse orientation of VV1 could increase the activity of beta-galactosidase with 10.9 and 3.8 times and those of VV16 could increase by 9.0 times and 4.1 times respectively. The enhancing activity of the element was on transcription level. An expression vector harboring prokaryotic enhancer-like sequence VV1 was constructed. Using this vector the antiviral activity of interferon alpha-2b was increased by 2.6 times in comparison with the original expression plasmid.

CONCLUSIONTwo enhancer-like sequences were screened from vaccinia virus genome. Interferon gene was highly expressed by using an expression vector harboring enhancer-like sequences.

Enhancer Elements, Genetic ; Genetic Vectors ; genetics ; Interferon-alpha ; biosynthesis ; genetics ; pharmacology ; Plasmids ; Recombinant Proteins ; Vaccinia virus ; genetics

For rapid and accurate screening of recombinant modified vaccinia virus Ankara (rMVA) that satisfied the quality standards of clinical trials, a novel shuttle vector that can delete the marker gene automatically during virus propagation was construted: pZL-EGFP. To construct the pZL-EGFP, the original shuttle vector pSC11 was modified by replacing the LacZ marker gene with enhanced green fluorescent protein (EGFP) and then inserting homologous sequences of TKL into the flank regions of EGFP. Baby hamster kidney (BHK)-21 cells were cotransfected with pZL-EGFP and MVA, and underwent ten passages and one plaque screening to obtain the EGFP-free rMVA carrying the exogenous gene. Resulting rMVA was tested by polymerase chain reaction and western blotting to verify pZL-EGFP function. A novel shuttle vector pZL-EGFP containing an EGFP marker gene which could be deleted automatically was constructed. This gene deletion had no effect on the activities of rMVA, and the exogenous gene could be expressed stably. These results suggest that rMVA can be packaged efficiently by homologous recombination between pZL-EGFP and MVA in BHK-21 cells, and that the carried EGFP gene can be removed automatically by intramolecular homologous recombination during virus passage. Meanwhile, the gene deletion had no influence on the activities of rMVA and the expression of exogenous target gene. This study lays a solid foundation for the future research.
Animals ; Biomarkers ; Cricetinae ; Epithelial Cells ; virology ; Gene Deletion ; Genetic Engineering ; methods ; Genetic Vectors ; genetics ; metabolism ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Recombination, Genetic ; Vaccinia ; virology ; Vaccinia virus ; genetics ; physiology ; Virus Replication

To construct a recombinant vaccinia virus RVJ1175M2 expressing influenza A3 virus (H3N2) M2 gene, full length gene encoding influenza virus (H3N2) M2 protein was amplified with PCR and cloned into plasmid pJSC1175 which was used for homologous recombination with vaccinia virus Tiantan strain. Along with this, a recombinant vaccinia virus RVJ1175M2 containing the M2 gene was subsequently constructed. It was identified by PCR that the gene of M2 protein was inserted into the TK locus of vaccinia virus Tiantan strain correctly and M2 protein was expressed by recombinant vaccinia virus RVJ1175M2 effectively. Two electrophoretic bands of M2 protein expressed by the infected HeLa cells, one of 15kD and the other of 13kD in accordance with related documents, was deteced by Western-blot. M2 protein distributing on the surface of the infected cells was demonstrated by immunofluorescence and flow cytometry. The results suggested that recombinant vaccinia virus RVJ1175M2 could express M2 protein effectively, this laid a foundation for comparative research on the immune effect of universal vaccine of influenza virus with different kinds of vaccine expressing M2 protein.
HeLa Cells ; Humans ; Influenza A Virus, H3N2 Subtype ; genetics ; Influenza Vaccines ; immunology ; Polymerase Chain Reaction ; Recombinant Proteins ; biosynthesis ; Vaccines, Synthetic ; immunology ; Vaccinia virus ; genetics ; Viral Matrix Proteins ; genetics

OBJECTIVEB8R gene encodes a secreted protein with homology to IFN-gamma receptor, which neutralizes the antiviral and immunological regulation activities of IFN-gamma. To improve the safety of vaccinia virus vector, an attenuated recombinant vaccinia virus with the B8R gene deletion from Tiantan vaccine strain (VTT) was constructed.

METHODSThe transfer vectors were generated by joining B8R left flank, B8R right flank, vv promoter, LacZ, multicloning site and pBRSK fragments. The recombinant viruses VTTdeltaB8RLacZ (VTT with B8R deletion and LacZ insertion) were constructed by homologous recombination.

RESULTSThe B8R deletion mutants were confirmed by dot blot with B8R gene probe and PCR amplification. The replication ability of VTTdeltaB8RLacZ strain in vitro was similar to that of the VTT. The skin lesions formed by VTTdeltaB8RLacZ (10(6) pfu) were significantly smaller and healed faster than those formed by VTT when injected intradermally to the rabbits,and no visible ulceration occurred. Meanwhile LacZ in VTKgpedeltaB8RLacZ was expressed stably.

CONCLUSIONSThe attenuated vector with B8R gene deletion improves the safety of recombinant vaccinia virus vaccine B8R locus may be used as a new site for insertion of foreign genes in vaccinia virus vector.

Animals ; Cell Line ; Chick Embryo ; Gene Deletion ; Genetic Vectors ; Humans ; Rabbits ; Receptors, Interferon ; genetics ; physiology ; Recombination, Genetic ; Vaccines, Attenuated ; immunology ; Vaccinia virus ; genetics ; immunology ; pathogenicity ; Virulence ; Virus Replication

To investigate the genetic stability (including the vector of vaccinia virus and six foreign genes: gp160, gag, pol, rev, tat and nef) of the HIV-1 non-replicating recombinant vaccinia virus (rNTV-C). rNTV-C was serially passaged to passage 25 (P25) in primary chicken embryo fibroblast (CEF). P9, P12, P15 and P25 were selected to study the genetic stability in four aspects, including the genetic stability of viral vector, the genetic stability of six foreign genes, the expressing stability of foreign genes and the genetic loss of foreign genes. The results showed that the viral vector was non-replicated vaccinia virus of Tiantan strain and was passaged stably; foreign gene sequences matched with designed sequences, the insert sites were right, and the nucleotide mutation rate was less than one over ten thousands within different passages of rNTV-C; the target proteins could be expressed effectively, and the expression level was stable within different passages of rNTV-C; the genetic loss of gag and nef was less than 5% within different passages of rNTV-C. The above results provided important data for the vaccine production.
Animals ; DNA, Recombinant ; genetics ; Fibroblasts ; metabolism ; virology ; Gene Expression ; Genes, Viral ; genetics ; Genetic Engineering ; methods ; Genetic Vectors ; genetics ; HIV-1 ; genetics ; Sequence Analysis, DNA ; Vaccinia virus ; genetics

OBJECTIVETo develop a recombinant vaccinia virus vaccine expressing HPV58 E7 and to determine its immuno-protective activity in mice bearing HPV58 E7+ tumor.

METHODSE7 DNA was amplified and cloned from a plasmid containing HPV58 E7 genome by PCR. To abolish its transforming activity, the nucleotides coding for amino acid residues at positions 24 and 92 were modified by site-directed mutagenesis so that cysteine was substituted by glycine. Balb/c 3T3 cells were transfected with mE7. The expression of E7 protein by the mE7-transfected Balb/c cells was confirmed by immunofluorescence staining. The transfected cells were observed in vitro for anchorage-independent growth and tumorigenesis in nude mice. Recombinant E7 vaccinia virus vaccine was constructed by homologous recombination of HPV58 E7 vaccinia expression plasmid and vaccinia virus (Tiantan stain). The immuno-protective activity of the vaccines was determined by tumor growth inhibition and cytotoxic T lymphocytes (CTL) induction in vaccine-immunized syngeneic mice.

RESULTSSubstitution of cysteine by glycine at both positions 24 and 92 of HPV58 E7 abolished its transforming activity. Growth of HPV E7+ tumor in mice immunized with the recombinant vaccinia virus expressing HPV58 E7 was inhibited, and the surviving time of the immunized mice was prolonged. CTL activity was induced as revealed by in vitro cytotoxicity assay using E7+ tumor cells as target cells.

CONCLUSIONSHPV58 E7, with its transforming potential abolished, may be used as vaccine for immunotherapy of patients with HPV 58 related cancers.

Animals ; Mice ; Mice, Inbred BALB C ; Mutagenesis, Site-Directed ; Oncogene Proteins, Viral ; genetics ; Papillomaviridae ; genetics ; immunology ; T-Lymphocytes, Cytotoxic ; immunology ; Transfection ; Vaccines, Synthetic ; immunology ; Vaccinia virus ; genetics ; immunology

UNLABELLEDA novel double expression shuttle vector named pLR-gpt was constructed for marker-free recombinant modified vaccinia virus Ankara generation. A delectable Eco gpt marker was adopted with Cre/LoxP DNA recombination system and a BHK-21 cell line that can express Cre enzyme. Eco gpt gene controlled by P7.5 promoter from Vaccinia virus was cloned between two LoxP sites in the same direction. Additionally, two multiple cloning site under control of other two Vaccinia virus promoters were constructed outside LoxP sites. With this new transfer vector, Eco gpt marker in rMVA can be deleted on BHK-Cre with interaction between Cre enzyme and LoxP sequence. In order to verify the efficacy of this system, ORF5 and ORF6 gene of Porcine reproductive and respiratory syndrome virus (PRRSV) NJ-a strain were cloned into two multiple cloning sites of pLR-gpt to construct recombinant plasmid pLR-ORFS/ORF6. Homologous recombination between pLR-ORF5/ORF6 and wtMVA on BHK-21 cell was mediated by liposome by infecting cells with 0.01 MOI wtMVA two hours before transfection. After twelve cycles of selection, recombinant MVA with selecting marker Eco gpt was obtained and named as rMVAgpt-GP5/M. By infecting BHK-Cre, the Eco gpt marker in rMVAgpt-GP5/M was deleted and this rMVA was named as rMVA-GP5/M. Expression of GP5 and M protein was identified with Western blotting and IFA. Results from PCR and biological study for rMVA indicated that Eco gpt marker was completely deleted.

CONCLUSIONSdouble expression transfer vector for marker-free recombinant Modified vaccinia virus Ankara generation was successfully constructed, and works well in MVA expression system.

Cell Line ; Cloning, Molecular ; DNA, Recombinant ; genetics ; Escherichia coli Proteins ; genetics ; Genetic Vectors ; genetics ; Pentosyltransferases ; genetics ; Porcine respiratory and reproductive syndrome virus ; genetics ; Vaccinia virus ; genetics ; Viral Envelope Proteins ; genetics ; Viral Matrix Proteins ; genetics

BACKGROUNDTo select the mutants of HPV type 16 E6 and E7 genes suitable for construction of vaccine for treatment of cervical cancer.

METHODSE6 and E7 genes were modified by site-directed mutagenesis. Several recombinant vaccina viruses were constructed by inserting the E6 or E7 mutants into the genome of vaccina virus Tiantan strain and employed to study their antigenicity.

RESULTSWestern blot assay showed that the E6 ?mutant? with substitution of Gly for Leu at amino acid site 50 and E7 mutant with substitution of Gly for Cys-24 and Glu-26 had no effect on their stability and antigenicity, but change of the Cys at position 91 of E7 dramatically reduced its stability and antigencity. Conclusion The results confirmed that the Zinc-finger structure at the E7 C-terminal? plays an important role in the integrity and stability of E7 protein.

Animals ; Antibodies, Viral ; biosynthesis ; Female ; Mice ; Mice, Inbred C57BL ; Mutagenesis, Insertional ; Oncogene Proteins, Viral ; genetics ; immunology ; Papillomaviridae ; genetics ; Papillomavirus E7 Proteins ; Repressor Proteins ; Vaccinia virus ; immunology ; Zinc Fingers

Orthopoxvirus vector has a broad prospect in recombinant vaccine research, but the rarely severe side-effect impedes its development. Vaccinia virus and Cowpox virus of Orthopoxvirus have broad host range, and they have typical host range genes as K1L, CP77 and C7L. These three genes affect host range of Vaccinia virus, disturb the cell signaling pathways, suppress immune response and are related to virulence.
Cell Line ; Cowpox virus ; genetics ; immunology ; pathogenicity ; physiology ; Genetic Vectors ; Host Specificity ; genetics ; Orthopoxvirus ; genetics ; immunology ; pathogenicity ; physiology ; Signal Transduction ; Vaccines, Synthetic ; immunology ; Vaccinia virus ; genetics ; immunology ; pathogenicity ; physiology ; Viral Proteins ; genetics ; metabolism ; Viral Vaccines ; immunology ; Virulence