Equine interferon-gamma (eIFN-gamma) expressed both in E. coli and baculovirus were evaluated for antiviral activity against recombinant Vesicular Stomatits Virus expressing green fluorescence protein (rVSV-GFP) in EFK-78 cells. The assays were conducted in 96-well plate. Virus infectivity was measured by quantifying GFP-positive cells, instead of quantifying the CPE reduction. Prior to infection of EFK-78 cells with rVSV-GFP, the cells were incubated with eIFN-gamma. The GFP expression in the EFK-78 cells dramatically decreased in the cells treated with eIFN-gamma in a dose-dependent manner, comparing with the mock-treated cells. The titers of antiviral activity were 1 x 10(3) AU/mL and 1 x 10(5) AU/mL of eIFN-gamma expressed from E. coli and baculovirus, respectively. The antiviral activities of the recombinant eIFN-gamma were highly efficient and specific, as it was blocked by mAbs against eIFN-gamma.
Animals ; Antibodies, Monoclonal ; immunology ; Antiviral Agents ; metabolism ; pharmacology ; Baculoviridae ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Green Fluorescent Proteins ; metabolism ; Horses ; Interferon-gamma ; biosynthesis ; genetics ; pharmacology ; Recombinant Proteins ; Vesicular stomatitis Indiana virus ; drug effects ; metabolism

Objective:To confirm the possible pathogen causing an outbreak of respiratory infectious disease in Beijing.Methods:Oropharyngeal swabs were collected from 14 cases with fever and detected by RT-PCR for respiratory viruses and bacteria. For specimens positive for adenoviruses, Fiber, Hexon and Penton gene fragments were amplified with specific primers and sequenced. BLAST and phylogenetic tree were used for sequence analysis.Results:All of the 14 specimens were adenovirus-positive. BLAST analysis of the sequences of Fiber, hexon and Penton genes showed that the 14 cases were all caused by adenovirus 3. The phylogenic tree analysis indicated that this adenovirus was closely related to an adenovirus of 3a51 genotype (GenBank No: KF268123) isolated in the USA in 2007.Conclusions:Human adenovirus genotype 3a51 caused this outbreak of respiratory infectious disease in Beijing.