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.

Infectious bovine rhinotracheitis viral gG expression and gG-ELISA development / 生物工程学报

Taking the genome DNA of Infectious Bovine Rhinotracheitis Virus (IBRV) as the template, the gG gene was amplified with PCR and cloned into the T cloning vector pMD18-T. After being identified by restriction digestion and DNA sequencing, the insert was subcloned into the expression vector pGEX-KG. Sodium docecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot assay showed that this gene was expressed as both soluble form and inclusion body by the transformed E. coli BL21 strain (DE3). The fusion protein was purified and used as the coating antigen to develop the indirect Enzyme-Linked Immunosorbent Assay (ELISA). Comparison between this gG-ELISA and commercial IBRV gB-ELISA Kit (IDEXX) was made in the detection of 380 cow serum samples. The results demonstrated an agreement of 92%. By using this novel gG-ELISA, 1248 cow serum samples were tested and the average positive rate of IBRV antibodies for imported cows is 21.7%, while the positive rate ranged greatly from 0.0%-41.5% for Hubei local Chinese Black and White Dairy Cows.