RESUMO
In the present study, we developed a complete process to produce in insect cells a high amount of the ectodomain of rabies virus glycoprotein G (GE) as suitable antigen for detecting anti-rabies antibodies. Using the baculovirus expression vector system in Sf9 insect cells combined with a novel chimeric promoter (polh-pSeL), the expression level reached a yield of 4.1 ± 0.3 mg/L culture, which was significantly higher than that achieved with the standard polh promoter alone. The protein was recovered from the cell lysates and easily purified in only one step by metal ion affinity chromatography, with a yield of 95% and a purity of 87%. Finally, GE was successfully used in an assay to detect specific antibodies in serum samples derived from rabies-vaccinated animals. The efficient strategy developed in this work is an interesting method to produce high amounts of this glycoprotein.
RESUMO
Feline interferon beta is a cytokine that belongs to the type I IFN family, with antitumor, antiviral and immunomodulatory functions. In this work, recombinant feline interferon beta (rFeIFNß) was expressed in insect larvae that constitute important agronomic plagues. rFeIFNß accumulated in the hemolymph of Spodoptera frugiperda larvae infected with recombinant baculovirus and was purified by Blue-Sepharose chromatography directly from larval homogenates on day 4 post-infection. rFeIFNß was recovered after purification with a specific activity of 1 × 106 IU mg-1. By this method, we obtained 8.9 × 104 IU of purified rFeIFNß per larva. The product was biologically active in vitro, with an antiviral activity of 9.5 × 104 IU mL-1, as well as a potent antitumor activity comparable to that of the commercial FeIFNω. The glycosylation of rFeIFNß was confirmed by peptide-N-glycosidase F digestion. Our findings provide a cost-effective platform for large-scale rFeIFNß production in laboratory research or veterinary medicine applications.
