The nucleotide sequence of the VP1 (1D) and partial 3D polymerase (3Dpol) coding regions of the foot and mouth disease virus (FMDV) vaccine strain A/Iran87, a highly passaged isolate (~150 passages), was determined and aligned with previously published FMDV serotype A sequences. Overall analysis of the amino acid substitutions revealed that the partial 3Dpol coding region contained four amino acid alterations. Amino acid sequence comparison of the VP1 coding region of the field isolates revealed deletions in the highly passaged Iranian isolate (A/Iran87). The prominent G-H loop of the FMDV VP1 protein contains the conserved arginine-glycine-aspartic acid (RGD) tripeptide, which is a well-known ligand for a specific cell surface integrin. Despite losing the RGD sequence of the VP1 protein and an Asp26-->Glu substitution in a beta sheet located within a small groove of the 3Dpol protein, the virus grew in BHK 21 suspension cell cultures. Since this strain has been used as a vaccine strain, it may be inferred that the RGD deletion has no critical role in virus attachment to the cell during the initiation of infection. It is probable that this FMDV subtype can utilize other pathways for cell attachment.
Amino Acid Sequence ; Amino Acid Substitution ; Antigens, Viral/chemistry/*genetics/metabolism ; Capsid Proteins/chemistry/*genetics/metabolism ; Cloning, Molecular ; Foot-and-Mouth Disease Virus/classification/*genetics/*metabolism ; Gene Expression Regulation, Viral ; Molecular Sequence Data ; Phylogeny ; Viral Nonstructural Proteins/chemistry/*genetics/metabolism

Hepatitis C virus (HCV) is a positive sense, single-stranded RNA virus in the Flaviviridae family. It causes acute hepatitis with a high propensity for chronic infection. Chronic HCV infection can progress to severe liver disease including cirrhosis and hepatocellular carcinoma. In the last decade, our basic understanding of HCV virology and life cycle has advanced greatly with the development of HCV cell culture and replication systems. Our ability to treat HCV infection has also been improved with the combined use of interferon, ribavirin and small molecule inhibitors of the virally encoded NS3/4A protease, although better therapeutic options are needed with greater antiviral efficacy and less toxicity. In this article, we review various aspects of HCV life cycle including viral attachment, entry, fusion, viral RNA translation, posttranslational processing, HCV replication, viral assembly and release. Each of these steps provides potential targets for novel antiviral therapeutics to cure HCV infection and prevent the adverse consequences of progressive liver disease.
Antigens, CD81/metabolism ; Genome, Viral ; Hepacivirus/genetics/*physiology ; Humans ; RNA, Viral/metabolism ; Scavenger Receptors, Class B/metabolism ; Viral Envelope Proteins/chemistry/metabolism ; Viral Nonstructural Proteins/chemistry/metabolism ; Virus Assembly ; Virus Internalization ; Virus Replication

In this study, Recombinant baculoviruses rBac-NF and rBac-NG were generated for expressing F and G proteins Nipah virus (NiV) . The expression of recommbinant G (rNG) and F (rNF) protein in rBac-NF and rBac-NG infected cells were confirmed by western-blot. Both rNG and rNF showed sensitive and specific antigenic reaction to rabbit serum anti-Nipah virus in indirect immunofluorescence detection and indirect ELISA. Immunization with rBac-NF and rBac-NG infected insect cells elicited G ad F protein specific antibody responses in mice. Furthermore, the G ad F specific antibodies could neutralize the infectivity of the VSVdeltaG* F/G, the NiV F and G envelope glycoproteins psudotyped recombinant Vesicular Stomatitis Virus expressing green fluorescence protein. The results demonstrated F and G protein expressed by the recombinant baculoviruses could be safe economic diagnostic antigens for the surveillance and monitoring of NiV and promising subunit vaccines for the prevention of NiV.
Animals ; Antigens, Viral ; immunology ; Baculoviridae ; genetics ; metabolism ; Mice ; Mice, Inbred BALB C ; Nipah Virus ; chemistry ; genetics ; Rabbits ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Recombination, Genetic ; Viral Envelope Proteins ; biosynthesis ; genetics ; immunology

Antibodies, Monoclonal ; chemistry ; immunology ; Antigens, Viral ; chemistry ; genetics ; immunology ; Binding Sites ; Capsid Proteins ; chemistry ; genetics ; immunology ; Epitopes ; chemistry ; genetics ; immunology ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; Hepatitis E ; immunology ; prevention & control ; virology ; Hepatitis E virus ; chemistry ; immunology ; Humans ; Molecular Docking Simulation ; Mutagenesis, Site-Directed ; Peptide Mapping ; Protein Binding ; Recombinant Proteins ; chemistry ; genetics ; immunology ; Viral Hepatitis Vaccines ; administration & dosage ; biosynthesis

Hepatitis E is an acute hepatitis casused by hepatitis E virus (HEV) in developing countries, where it occurs as cases sporadic and in epidemics form. The causative agent, hepatitis E virus, is transmitted primarily by the fecal-oral route. HEV is icosahedron non-enveloped virus, and its genome is a single-stranded, positive-sense, 3'-polyadenylated RNA about 7.5 kb in length. It contains three open reading frames (ORFs). Of which ORF1 codes for a polyprotein of 1693 amino acids and contain domains homologous to a viral methyltransferase, a papainlike cysteine protease, an RNA helicasre, and an RNA-dependent RNA polymerase, besides the most hypervariable region of the HEV genome. And ORF3 codes for a 123-amino-acide-long polypeptide with unknown function. While the major viral capsid protein (pORF2, ORF2 codes) of 660 amino acid was showed to contain the protective epitope. The bacterially expressed polypeptide disignated as NE2 has been proved to be a protective antige. And the anti-NE2 monoclonal antibodies (mAb) was screend, two of these mAbs 8C11 and 8H3 were showed to be against separate conformational neutralization epitope of hepatitis E virus (HEV). And these two mAb were used to screen for binding peptides from a 7-peptides phage display library. After four rounds of panning, tweenty-one positive monoclonal phages (11 for 8C11, and 10 for 8H3) were selected and the inserted fragments were sequenced. The DNA sequence coding for the obtained dominant peptide 8C11 (N'-His-Pro-Thr-Leu-Leu-Arg-Ile-C', named 8C11A) and 8H3 (N'-Ser-Ile-Leu-Pro-Tyr-Pro-Tyr-C', named 8H3A) were then synthesized and cloned to insert between amino acid 78 to 83 of hepatitis B core antigen (HBcAg), then expressed in E. coli. The recombinant proteins aggregate into homodimer or polymer on SDS-PAGE, and could bind with mAb 8C11 and 8H3 in Western blotting. Respectively, the recombinant protein C8C11A showed to be dimer mainly, which can bind with mAb 8C11. The monomer and dimer of C8H3A are in the same amount on SDS-PAGE, but only the dimer could bind with mAb 8H3 on Western blotting. The renatured recombinant proteins were all showed to aggregate into virus like particles which were similar as HBcAg on transmission electron micrograph. The dominant peptide 8H3A (N'-Ser-Ile-Leu-Pro-Tyr-ProTyr-C') that selected out by mAb 8H3 was further chemo-synthesized, and its binding activity was confirmed by BIAcore biosensor. The result showed that this 7-peptide can bind with mAb 8H3 in a big Ka and Kd form, which means the binding is not stable. These results implicated that conformational dependent neutralization epitope could be partially modeled by short peptide, which provided a feasible route for subunit vaccine development.
Amino Acid Sequence ; Animals ; Antibodies, Monoclonal ; immunology ; Blotting, Western ; Electrophoresis, Polyacrylamide Gel ; Epitopes ; chemistry ; genetics ; immunology ; metabolism ; Hepatitis B Core Antigens ; genetics ; metabolism ; Hepatitis E virus ; genetics ; immunology ; metabolism ; Mice ; Microscopy, Electron ; Molecular Sequence Data ; Peptide Library ; Peptides ; chemistry ; genetics ; immunology ; metabolism ; Recombinant Proteins ; genetics ; immunology ; metabolism ; ultrastructure ; Sequence Homology, Amino Acid ; Viral Proteins ; chemistry ; genetics ; immunology ; metabolism ; ultrastructure

Animals ; Antigens, CD ; chemistry ; genetics ; metabolism ; Antiviral Agents ; chemistry ; metabolism ; GPI-Linked Proteins ; HIV Infections ; metabolism ; virology ; HIV-1 ; genetics ; physiology ; Human Immunodeficiency Virus Proteins ; genetics ; metabolism ; Humans ; Membrane Glycoproteins ; chemistry ; genetics ; metabolism ; Protein Binding ; Viral Regulatory and Accessory Proteins ; genetics ; metabolism ; Virus Shedding

BST-2 plays an important role in host innate immune response via inhibiting the release of HIV-1. HIV-1 accessory protein Vpu can interact with BST-2 through its transmembrane domains, degrade BST-2, and decrease BST-2 that are transported to the cell surface, thus anti-virus function of BST-2 is antagonized. In our study, we constructed plasmid RB connecting Rluc to the N-termimal of BST-2, and plasmid VE connecting EYFP to the C-terminal of Vpu. The two fusion proteins were co-expressed in 293 cells, and the interaction between the two proteins was detected via BRET method. And we further established a stable 293 cell line of dual-expression. By using BRET method, and the interaction between BST-2 and Vpu transmembrane domain as the target, a high-throughput screening assay was created that was expected to seek novel interaction inhibitors.
Antigens, CD ; chemistry ; genetics ; metabolism ; Cell Line ; GPI-Linked Proteins ; chemistry ; genetics ; metabolism ; HIV Infections ; genetics ; metabolism ; virology ; HIV-1 ; genetics ; metabolism ; High-Throughput Screening Assays ; methods ; Human Immunodeficiency Virus Proteins ; genetics ; metabolism ; Humans ; Protein Binding ; Protein Structure, Tertiary ; Viral Regulatory and Accessory Proteins ; genetics ; metabolism

HLA-A* 2402 is one of the most frequently encountered HLA-A alleles in East Asian populations. In order to study the CD8+ T cell responses in Chinese populations, we have described the generation and functional test of HLA-A* 2402 tetramer loaded with HCMV pp65(341-349) peptide (QYDPVAALF, QYD). The cDNA of HLA-A* 2402 heavy chain was cloned by RT-PCR from one of the donors. DNA fragment encoding the ectodomain of HLA-A* 2402 heavy chain fused at its carboxyl-terminal a BirA substrate peptide (BSP) was amplified by PCR with the cloned heavy chain cDNA as a template. The wild-type gene of HLA-A* 2402-BSP was not expressed in Escherichia coli (E. coli), while mutant HLA-A* 2402-BSP gene with optimized codons was overexpressed as inclusion bodies in E. coli. Furthermore, the soluble HLA-A* 2402-QYD monomers were generated by in vitro refolding of washed inclusion bodies in the presence of beta2-microglobulin and QYD peptide. The tetramer was subsequently formed by mixing HLA-A* 2402-QYD monomers with streptavidin-PE at a molar ratio of 4:1. Flow cytometry analysis indicated that this tetramer possessed binding activity with specific CTL from HLA-A24+ donors and the frequencies of tetramer-binding CTL were 0.09% - 0.37% within total CD8+ T cells. This tetrameric agent provides a powerful tool to explore the secrets of CTL responses against HCMV antigens in HLA-A* 2402 individuals.
Amino Acid Sequence ; CD8-Positive T-Lymphocytes ; cytology ; metabolism ; Carbon-Nitrogen Ligases ; metabolism ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; Escherichia coli Proteins ; metabolism ; Flow Cytometry ; Gene Expression ; HLA-A Antigens ; chemistry ; genetics ; metabolism ; HLA-A24 Antigen ; Humans ; Oligopeptides ; genetics ; metabolism ; Phosphoproteins ; chemistry ; genetics ; metabolism ; Protein Multimerization ; Recombinant Fusion Proteins ; chemistry ; genetics ; metabolism ; Repressor Proteins ; metabolism ; Substrate Specificity ; T-Lymphocytes, Cytotoxic ; cytology ; metabolism ; Viral Matrix Proteins ; chemistry ; genetics ; metabolism

To develop a sensitive and specific ELISA for detection of antibodies to the nonstructural protein of FMDV. We cloned and expressed FMDV nonstructural protein 3AB in Escherichia coli expression system. The recombinant protein 3AB was purified with Ni-NTA HisBind Resins and characterized by Western blotting. An indirect ELISA based on purified protein 3AB as a coating antigen was established. The specificity and sensitivity of this assay were evaluated by comparison with a commercial 3ABC-ELISA kit in detecion of serum samples. The results showed that the recombinant protein 3AB was expressed as a formation of inclusion bodies in Escherichia coli. The purified protein could specificially react with FMDV infection antibodies in Western blotting assay, but no reaction with the immune antibodies induced with vaccine. Two assays were no significant differences in specificity and sensitivity for detection of field samples (P>0.05). Therefore, we speculated that the recombinant protein 3AB is a promising molecular marker, which may effectively differentiate FMD-infected from vaccinated animals in a herd.
Animals ; Antibodies, Viral ; analysis ; Antigens, Viral ; biosynthesis ; genetics ; immunology ; Cattle ; Cattle Diseases ; diagnosis ; immunology ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; genetics ; metabolism ; Foot-and-Mouth Disease ; diagnosis ; immunology ; Foot-and-Mouth Disease Virus ; chemistry ; genetics ; isolation & purification ; Genetic Vectors ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Viral Nonstructural Proteins ; biosynthesis ; genetics ; immunology

In the face of the worldwide threat of severe acute respiratory syndrome (SARS) to human life, some of the most urgent challenges are to develop fast and accurate analytical methods for early diagnosis of this disease as well as to create a safe anti-viral vaccine for prevention. To these ends, we investigated the antigenicity of the spike protein (S protein), a major structural protein in the SARS-coronavirus (SARS-CoV). Based upon the theoretical analysis for hydrophobicity of the S protein, 18 peptides were synthesized. Using Enzyme-Linked Immunosorbent Assay (ELISA), these peptides were screened in the sera from SARS patients. According to these results, two fragments of the S gene were amplified by PCR and cloned into pET-32a. Both S fragments were expressed in the BL-21 strain and further purified with an affinity chromatography. These recombinant S fragments were confirmed to have positive cross-reactions with SARS sera, either by Western blot or by ELISA. Our results demonstrated that the potential epitope regions were located at Codons 469-882 in the S protein, and one epitope site was located at Codons 599-620. Identification of antigenic regions in the SARS-CoV S protein may be important for the functional studies of this virus or the development of clinical diagnosis.
Antigens, Viral ; immunology ; Chromatography, High Pressure Liquid ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Enzyme-Linked Immunosorbent Assay ; Genetic Vectors ; Humans ; Mass Spectrometry ; Membrane Glycoproteins ; genetics ; immunology ; metabolism ; Molecular Weight ; Peptide Fragments ; chemistry ; Recombinant Proteins ; genetics ; immunology ; SARS Virus ; genetics ; immunology ; metabolism ; Spike Glycoprotein, Coronavirus ; Viral Envelope Proteins ; genetics ; immunology ; metabolism