Chimeric rabies glycoprotein with a transmembrane domain and cytoplasmic tail from Newcastle disease virus fusion protein incorporates into the Newcastle disease virion at reduced levels

Rabies remains an important worldwide health problem. Newcastle disease virus (NDV) was developed as a vaccine vector in animals by using a reverse genetics approach. Previously, our group generated a recombinant NDV (LaSota strain) expressing the complete rabies virus G protein (RVG), named rL-RVG. In this study, we constructed the variant rL-RVGTM, which expresses a chimeric rabies virus G protein (RVGTM) containing the ectodomain of RVG and the transmembrane domain (TM) and a cytoplasmic tail (CT) from the NDV fusion glycoprotein to study the function of RVG's TM and CT. The RVGTM did not detectably incorporate into NDV virions, though it was abundantly expressed at the surface of infected BHK-21 cells. Both rL-RVG and rL-RVGTM induced similar levels of NDV virus-neutralizing antibody (VNA) after initial and secondary vaccination in mice, whereas rabies VNA induction by rL-RVGTM was markedly lower than that induced by rL-RVG. Though rL-RVG could spread from cell to cell like that in rabies virus, rL-RVGTM lost this ability and spread in a manner similar to the parental NDV. Our data suggest that the TM and CT of RVG are essential for its incorporation into NDV virions and for spreading of the recombinant virus from the initially infected cells to surrounding cells.

Study on the DNA immunogenicity of fusion and attachment glycoproteins of Nipah virus / 病毒学报

The two mammalian codon optimized genes, F and G genes of Nipah virus, were generated by assembly PCR, and inserted into mammalian expression vector pCAGGS under chicken beta-actin promoter to construct pCAGG-NiV-F and pCAGG-NiV-G. Syncytium formation was induced in BHK cells by plasmid pCAGG-NiV-F and pCAGG-NiV-G transfection, which indicate recombination proteins F and G were expressed in BHK cell and possessed good biologic activity. Six-week-old female BALB/c mice were intramuscularly primed with 100 microg pCAGG-NiV-F, pCAGG-NiV-G or pCAGG-NiV-F+ pCAGG-NiV-G respectively, and boosted with same dose after 4 weeks. The sera were collected at 3 weeks post second boost. The serum IgG against Nipah virus F and G proteins was detected by indirect ELISA using recombinant Baculovirus expressed Nipah F and G glycoproteins. The results showed that specific antibodies possessed good sensitivity and specificity. Furthermore, the G and F proteins' specific antibodies could neutralize the infectivity of VSVdeltaG* F/G (the NiV F and G envelope glycoproteins psudotyped recombinant vesicular stomatitis virus expressing green fluorescence protein). And, pCAGG-NiV-G also induced higher titer of neutralizing antibody response than pCAGG-NiV-F did. The result indicates that DAN immunization is an efficient vaccine strategy against Nipah virus.

Expression of porcine gamma-interferon in recombinant baculovirus and determination of its antiviral activity / 生物工程学报

The full-length porcine interferon gamma(PoIFN-gamma) cDNA, including the secretion signal peptide coding region was recloned into honor plasmid pFastBac 1 of Bac-To-Bac Baculovirus Expression System. These recombinant plasmids, pFastBac -PoIFN-gamma, were transformed into DH(10Bac) host bacteria to get recombinant shuttle plasmids, rBacmid-PoIFN-gamma. Recombinant baculovirus, rBac-PoIFN-gamma, was generated for expressing PoIFN-gamma, by transfecting rBacmid-PoIFN-gamma with Cellfectin Reagent into sf9 insect cells. The expression of PoIFN-gamma in insect cells was confirmed by Western Blot, indirect immunofluorescence assay and indirect ELISA. The antiviral activity assay shows that PoIFN-gamma expressed by the rBac-PoIFN-gamma can efficiently inhibit the replication of the recombinant Vesicular Stomatitis Virus expressing green fluorescence protein in PK-15 cells. The antiviral activity of PoIFN-gamma can be specifically blocked by anti-PoIFN-gamma mouse serum. The antiviral titer of culture supernatant of insect cells infected by rBac-PoIFN-gamma is 2 x 10(4) IU/mL. The results demonstrat that the rBac-PoIFN-gamma can express rPoIFN-gamma efficiently and rPoIFN-gamma has high antiviral activity.

Study of fusion protein and attachment glycoprotein of Nipah virus expressed in recombinant baculovirus / 生物工程学报

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.