Establishment of a fluorescent real-time quantitative RT-PCR assay for detection of genotype 4 hepatitis E virus in swine stools / 病毒学报

The primers and probes for the Real-time RT-PCR were designed based on the multiple sequence (swine and humans HEV strains) alignments of the ORF3 region of genotype 4 HEV. A rapid, sensitive and stable TaqMan Real-time RT-PCR assay was established, and its specificity and sensitivity were assessed, and comparison of the Real-time RT-PCR with conventional and nested RT-PCR was performed. The results found that the crossing points showed linearly proportional to the logarithm of the input copy number. The correlation coefficient (R2) and the slope value of the standard curves with plasmid DNA were 0.994 and -3.312, respectively. The efficiency (E) of the PCR was 100%. Coefficients of variation values of the different diluted plasmid DNA were low in the same or different repeated experimental group. In addition, the assay was able to correctly detect genotype 4 HEV RNA from swine fecal samples. The sensitivity of established assay was 100-fold higher than that of conventional RT-PCR and 10-fold higher than nested RT-PCR.

Isolation and identification of swine NDV JL01 strain and phylogenetic analysis of F gene / 病毒学报

An outbreak of fever and dyspnea with high incidence rate and case fatality rate occurred among pigs in a pigfarm in Jilin province, China, in 2000. The paramyxovirus-like particles could be observed in lungs, spleens and kidneys of the dead pigs under the transmission electron microscope. A Newcastle disease virus (NDV) isolate designated as JL01 was determined as the causal agent for the disease outbreak. The purified virus was reinoculated into pigs, and then the pigs infected with the virus showed similar symptoms, and the HI antibody of NDV could be detected from the reinoculated pigs. The MDT, ICPI and EID50 of the JL01 isolate was 55.2h, 1.60 and 10(-7.5)/0.1 mL respectively. The F gene of JL01 was cloned and sequenced, and the results showed that the identities of F gene shared by JL01 and avirulent NDV reference strains were from 91.5% to 98.5%, and could be ascribed to NDV genotype I. Thus, the swine NDV JL01 strain should be an avirulent strain with gene variation, but the virulence of JL01 was just the same as velogenic strains.

Expression of AIV subtype H5HA, H7HA and H9HA hemagglutinin gene in Pichia pastoris / 生物工程学报

The expression of the hemagglutinins of Avian influenza virus H5 H7and H9 subtypes was studied in this article by Pichia pastoris, one of the eukaryotis expression systems. Three reconstructed expression plasmids and engineering strains, named pPIC9K-H5HA, pPIC9K-H7HA, pPIC9K-H9HA and GS115/pPIC9K-H5HA, GS115/pPIC9K-H7HA, GS115/pPIC9K-H9HA repectively, were obtained. The reconstructed yeast engineering strains were identified by MD and MM plate selecting and PCR. The induced interests proteins were examined by SDS-PAGE and Western-bloting,the results showed that the interest genes were expressed exactly. And this will be helpful in the future study of antigen detection and antibody detection kit, as well in the subunit vaccines developing.

Induction of apoptosis in human hepatoma cell line SMMC7721 by Newcastle disease virus HN gene / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the mechanisms of apoptosis induced in human hepatoma cell line SMMC7721 by plasmid pVHN constructed with Newcastle disease virus (NDV) HN gene.</p><p><b>METHODS</b>Twenty-four h after transfection with liposome-plasmid pVHN complexes in vitro, the mortality rate of SMMC7721 cells was determined by MTT staining and flow cytometry (FCM) with PI staining. The alteration of mitochondrial trans-membrane potential of the cells was detected by FCM with rhodamine 123 staining. Cell genomic DNA was detected by agarose electrophoresis. The activation of caspase-3 was assayed by its substrate color reaction.</p><p><b>RESULTS</b>Significant apoptosis was induced by transfection with plasmid pVHN into the cells for 24 h and the mortality rate was 50.0% (the mortality rate of control group was 5.2%). Genomic DNA was fragmented and mitochondrial trans-membrane potential was decreased, but caspase-3 activity increased.</p><p><b>CONCLUSION</b>Significant apoptosis in SMMC7721 cells can be induced by NDV HN gene. Apoptosis may be resulted from the decrease of mitochondrial trans-membrane potential and activation of Caspase-3.</p>

Construction of the nucleic vaccine pVVP3L-18HN and its antitumor effect on human laryngeal carcinoma / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>Nucleic vaccine of pVVP3IL-18HN expressing apoptin gene, Newcastle disease virus HN gene and IL-18 gene were constructed to observe the combinative antitumor effect of the above three genes.</p><p><b>METHODS</b>Eukaryotic expression plasmid pVVP3IL-18HN was constructed by inserting apoptin gene and fragment comprising fused IL-18HN gene and IRES promoter into the downstream of CMV promoter of vector pVAX1. The expression of inserted gene was identified by RT-PCR, indirect immunofluorescence and Western-blot. The recombinant plasmid was introduced into Hep-2 cells by liposome, then suppression rate of Hep-2 of different time and different quantity was calculated according to MTT results.</p><p><b>RESULT</b>The recombinant plasmid of pVVP3IL-18HN suppressed Hep-2 successfully and its suppression rate was up to 61.9% with 20 microg/ml, incubation of 72 hours.</p><p><b>CONCLUSION</b>The nucleic vaccine constructed pVVP3IL-18HN had antitumor effect on Hep-2. It may can be used to the therapy and research of laryngeal carcinoma.</p>

Selection of recombinant fowlpox virus coexpressing HIV-1 gag-gp120 and IL-6 / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To construct the recombinant fowlpox virus (rFPV) coexpressing HIV-1 gag-gp120 and hIL-6.</p><p><b>METHODS</b>The recombinant expressing plasmid pUTA-GE-IL6 was successfully constructed by inserting gag-gp120 gene and hIL-6 gene into the downstream of the combined promoter ATI-p7.5 and p7.5 tandem promoter respectively. After transfecting the plasmid into chicken embryonic fibroblast (CEF) cells preinfected with FPV 282E4 strain and selecting the recombinant virus under the pressure of BUdR. The recombinant virus was analyzed by nucleic acid probe hybridization and immunoblotting. In addition, the formation of virus-like particle and the expression of interested proteins in the recombinant virus-infected p815 cells were observed, and the immunogenicity of the recombinant virus was also analyzed.</p><p><b>RESULTS</b>There was colorable dot for the positive recombinant virus, immunoblotting analysis showed that the recombinant virus could expressed both gag-gp120 and IL-6. Virus-like particles (VLP) were formed in virus-infected cells, and the interested proteins could be expressed in mammalian cells infected by the recombinant virus. The immunity index from the immunized mice showed that the recombinant virus had good immunogenicity.</p><p><b>CONCLUSION</b>The recombinant fowlpox virus coexpressing gag-gp120 and IL-6 was successfully constructed, which may provide basis for the preparation of live vector genetic engineering vaccine and macromolecule particle vaccine against HIV-1.</p>

Expression and detection of recombinant directing toxin SL120 in Pichia pastoris / 生物工程学报

Anti-HIV-1 gp120 single chain antibody(scFv) gene and staphylococcus extoxin A(SEA) gene were inserted into vector pPIC9K. The recombinant plasmid was integrated into Pichia pastoris by electroporation. High level expression was performed by determining the Muts phenotype and screening muti-copy integrants. The recombinant protein was about 57kD and the production was 50.1 mg/L. It was shown that the two kinds of protein affected the conformation of each other by antibody affinity assay, but the recombinant targeting toxins could highly mediate CTLs to kill HIV-1 target cells.

Construction of recombinant fowlpox virus coexpressing gp120 of Chinese HIV-1 strain and IL-18 and its immunogenicity in mice / 生物工程学报

To screening out Chinese vaccine candidate against HIV-1, Chinese vaccine strain 282E4 of fowlpox virus was used as the vector to construct the recombinant fowlpox virus (rFPV) coexpressing gp120 of Chinese HIV-1 strain and IL-18, and the recombinant virus was indentified by PCR and Western blot. The specific DNA fragment could be amplified by PCR from the genome of rFPV. Western blot analysis showed that gp120 and IL-18 could be expressed not only in chicken embryo fibroblast (CEF) cells infected by rFPV, but also in mammalian cells infected by rFPV. After the recombinant fowlpox virus was inoculated into BALB/c mice, the spleen specific CTL activities and serum antibodies in the immunized mice were detected, which demonstrated that the rFPV had good immunogenicity and could induce BALB/c mice to produce specific humoral and cellular immunity. IL-18 palyed the role of immunoadjuvant. The study lays the basis on the preparation of genetic engineering live vector vaccine against HIV-1.

Expressing of N gene encoding nucleocapsid protein of vesicular stomatitis virus and elementary application in ELISA / 生物工程学报

The gene encoding the nucleocapsid (N) protein of vesicular stomatitis virus (VSV-NJ) was subcloned from pMD-VN5, and inserted into pBAD/Thio TOPO vector. The recombinant plasmid was identified by restriction analysis and PCR. It was sequenced to confirm the correct sequences and the correct junctional orientations of the inserted N gene. The results of SDS-PAGE and Western immunoblotting revealed that the N protein was expressed in Escherichia coli LGM194 in a high level and the recombinant fusion protein, which contained a N-terminal HP-Thioredoxin and a C-terminal polyhistidine tag. It had a molecular mass of approximately 63.5 kD and immunologically reactive activity. The recombinant protein was characterized and tested in an enzyme-linked immunosorbent assay (ELISA) format for potential application in the serodiagnosis of vesicular stomatitis using 186 serum samples from experimentally infected goats and guinea-pigs with VSV-NJ and VSV-IN, and from field origin and reference serum samples. The sensitivity and specificity of the ELISA were compared with those of the standard microtiter serum neutralization (MTSN) tests. The ELISA and MTSN test results were highly correlated for detection of VSV antibodies. The ELISA was as sensitive as the SN assay in detecting positive serum to VSV. The correlation between SN titers and ELISA titers was statistically significant. These data suggest that the recombinant fusion N protein of VSV could be used as a recombinant test antigen for the serodiagnosis of vesicular stomatitis. The ELISA based on the reconmbinant nucleocapsid protein may offer the best combination of rapidity, sensitivity, simplicity, economy, and laboratory biosafety of any of the methods yet developed for VSV serodiagnosis. This study lay on foundation for the development of the diagnosis methods in serology for VSV.

Effective Antitumor Activity of a Recombinant Vaccinia Virus Expressing Murine Interleukin 4

Vaccinia virus is the prototype orthopoxvirus that has been used as a vaccine strain for small pox. This virus has been used to express a variety of cellular and viral genes in mammalian cells at high levels. Interleukin-4 (IL-4) has been found to stimulate the proliferation of T cells and enhance the cytolytic activity of cytotoxic T lymphocytes. To test the immunotherapeutic potential of IL-4 delivered in vivo by poxvirus, a recombinant vaccinia virus expressing the murine IL-4 gene (RVVmIL-4) was constructed. A high level of IL-4 production was confirmed by infecting HeLa cells and measuring IL-4 in cell culture supernatant by ELISA. As a tumor model, two cell lines were used: the murine T leukemic line P388 and the murine breast cancer line TS/A. CDF1 mice were intraperitoneally inoculated with 1 x 105 cells of P388. Mice were injected at the same site with 5 x 105 PFU of recombinant vaccinia virus; first, 3 days after the injection of tumor cells and thereafter once every week for 3 weeks. Intraperitoneal injections of RVVmIL-4 significantly prolonged the survival time of mice inoculated with tumor cells. All mice injected with RVVmIL-4 remained alive for 30 days after the postinoculation of tumor cells, while 100% and 70% of the animals injected with saline or wild type vaccinia virus died, respectively. In another tumor model using TS/A, tumor was established by subcutaneously inoculating 2 x 105 tumor cells to BALB/c mice. After tumor formation was confirmed on day 4 in all mice, 5 x 106 PFU of RVVmIL-4 was inoculated subcutaneously three times, once every week for 3 weeks. The TS/A tumor was eradicated in two of the nine mice. Seven of the nine mice treated with RVVmIL-4 developed a tumor, but tumor growth was significantly delayed compared to those treated with saline or wild type vaccinia virus. These results indicate that recombinant vaccinia viruses may be used as a convenient tool for delivering immunomodulator genes to a variety of tumors.

Construction of HIV-2 gag recombinant fowlpox virus and its immune reactivity in mice / 中华传染病杂志

Objective To provide experimental evidences for developing a safe and effective re- combinant fowlpox virus which can prevent the infection of HIV-2.Methods A fowlpox virus(FPV) transferring vector was constructed by inserting HIV-2 gag gene to the downstream of a synthetic complex promoter ATI-p7.5?20 of vector pUTA2.Transfection was then carried out,and recombi- nant FPV(rFPV)was screened by 5'-bromo-deoxyuridine(BrdU),genome PCR and western blot detection.Balb/c mice were immunized with rFPV by muscular injection.Anti-HIV-2 antibody, CD4~+ and CD8~+ T-cell count and specific target-killing activity of spleen CTL in immunized mice were analyzed by ELISA,FACS and LDH release assay,respectively.Results A transferring vector pA- gag was constructed and confirmed by amplifying a fragment of 766 bp from the rFPV genome.Mean- while,HIV-2 multi-antibody-specific protein blot(55 000)was detected from the recombinant virus and the HIV-2 specific antibody was detected from the immunized Balb/c mice.HIV-2 specific target- killing activity of spleen CTL was observed in immunized mice.Conclusion A recombinant fowlpox virus expressing HIV-2 structural protein Gag has been obtained,and it can stimulate HIV-2-specific eelluar and humoral immune reactions in mice.