Characterisation of a New Molecule Based on Two E2 Sequences from Bovine Viral Diarrhoea-mucosal Disease Virus Fused To the Human Immunoglobulin Fc Fragment.

INTRODUCTION: Proper conformational arrangement of the E2 molecules of bovine viral diarrhoea-mucosal disease virus (BVD-MDV) is crucial to obtain an effective recombinant vaccine candidate against the disease. In this study, we characterised a new molecule composed of two distinct sequences of the E2 glycoprotein of BVD-MDV and the Fc fragment of human immunoglobulin (BVDE2Fc). MATERIALS AND METHODS: The chimaeric protein was expressed in mammalian cell lines of different species by adenoviral transduction and purified by immobilised metal-affinity chromatography. The N-glycans were profiled by HPLC, and the BVDE2Fc immunogenicity was assessed in male mice. The antigen-antibody reactions were evaluated by ELISA. RESULTS: The MDBK cell line was selected from among five for the final production of BVDE2Fc. After purification to over 90%, the N-glycan profile showed neutral and complex oligosaccharides. The mouse immunisation induced a strong humoral response, which produced antibodies able to attach to conformational epitopes on E2 molecules, while the Fc fragment barely contributed to the immune response. Additionally, BVDE2Fc attached to antibodies from bovine sera positive to distinct BVD-MDV subtypes, whereas the loss of BVDE2Fc structure during the deglycosylation process considerably diminished those interactions. CONCLUSION: These results demonstrate that the structure of E2 molecules arranged in tandem and attached to an Fc fragment could represent a viable design for future vaccine candidates against BVD-MD.

Multi-targeted gene silencing strategies inhibit replication of Canine morbillivirus.

BACKGROUND: Canine morbilivirus (canine distemper virus, CDV) is a highly contagious pathogen associated with high morbidity and mortality in susceptible carnivores. Although there are CDV vaccines available, the disease poses a huge threat to dogs and wildlife hosts due to vaccine failures and lack of effective treatment. Thus, the development of therapeutics is an urgent need to achieve rapid outbreak control and reduce mortality in target species. Gene silencing by RNA interference has emerged as a promising therapeutic approach against different human and animal viruses. In this study, plasmid-based short hairpin RNAs (shRNAs) against three different regions in either CDV nucleoprotein (N), or large polymerase (L) genes and recombinant adenovirus-expressing N-specific multi-shRNAs were generated. Viral cytopathic effect, virus titration, plaque-forming unit reduction, and real-time quantitative RT-PCR analysis were used to check the efficiency of constructs against CDV. RESULTS: In CDV-infected VerodogSLAM cells, shRNA-expressing plasmids targeting the N gene markedly inhibited the CDV replication in a dose-dependent manner, with viral genomes and titers being decreased by over 99%. Transfection of plasmid-based shRNAs against the L gene displayed weaker inhibition of viral RNA level and virus yield as compared to CDV N shRNAs. A combination of shRNAs targeting three sites in the N gene considerably reduced CDV RNA and viral titers, but their effect was not synergistic. Recombinant adenovirus-expressing multiple shRNAs against CDV N gene achieved a highly efficient knockdown of CDV N mRNAs and successful inhibition of CDV replication. CONCLUSIONS: We found that this strategy had strong silencing effects on CDV replication in vitro. Our findings indicate that the delivery of shRNAs using plasmid or adenovirus vectors potently inhibits CDV replication and provides a basis for the development of therapeutic strategies for clinical trials.

Expression and Characterization of Human Vascular Endothelial Growth Factor Produced in SiHa Cells Transduced with Adenoviral Vector.

The vascular endothelial growth factor (VEGF) is an essential factor to pathologic angiogenesis. Disruption of VEGF/VEGF receptor interaction in cancer patients inhibits the development of new and pre-existing tumor blood vessels. Consequently, VEGF becomes an important therapeutic target for handling solid tumors. In this work, human VEGF was produced in the culture supernatant of SiHa cells transduced with a replication-defective adenoviral vector (pAdhVEGF121) encoding this molecule. The 35 kDa VEGF121 homodimer was obtained from clarified culture media as a glycosylated protein. VEGF121 expression levels were strictly dependent on the adenoviral viral load used. VEGF121 was produced with purity over 98% after a single step chromatography by immobilized metal affinity chromatography. Additionally, VEGF121 binds Bevacizumab antibody with a KD of 7 nM. Biological characterization by mitogenic assay in HUVEC and ECV-304 cells showed that VEGF121 stimulates cell proliferation in a dose-dependent manner in both cells. Finally, the neovascularization activity of VEGF121 was demonstrated by vascular permeability assays in matrigel plug-bearing mice, showing significantly increased vasculature leakage after treatment with VEGF121. Consequently, transduction of SiHa cells with adenovirus is a suitable alternative for manufacture heterologous proteins of therapeutic interest.

[Steroid drugs and GM-CSF modulates activity of Egr-1 in glioma cells]. / Fármacos esteroides y el GM-CSF modulan la actividad de Egr-1 en células de glioma.

INTRODUCTION: The Egr-1 protein is a transcriptional factor responsive to early growth. Transcriptional regulation of the promoter has been described like responsive to physical stress, osmotic changes, and cellular growth marker. However, there is no report about the pharmacological effect on the transcriptional regulation in gliomas. Hereby we report the modulation of the Egr-1 promoter transcriptional activity induced by the Granulocytes Macrophages Colony Stimulating Factor (GM-CSF) and steroid drugs in human glioma cells (CH235-GM Grade II, U373-GM Grade III, D54-GM Grade IV) using a reporter system transduced by a recombinant adenoviral vector AdEgr-1/luc7. METHODS: Human glioma cells shows with different malignity grade (CH235-GM Grado II; U373-GM Grado III; D54-GM Grado IV) were transduced with no replicative adenoviral vector AdEgr-1/Luc7 and exposed to drugs as progesterone, ß-estradiol and betametasone, and GM-CSF. Transcriptional activity of the egr-1 promoter was quantified by Luciferase reporter gene, cloned downstream to the tata box. Luciferase activity was quantified from whole cell proteins using luminometry assays. RESULTS: U373-GM cell line with GM-CSF, shows an increment on transcriptional activity of Egr-1 promoter, also in endogen way. U373-GM showed a positive regulation of Egr-1, with steroid drugs on the times analyzed. Steroid drugs as progesterone, ß-estradiol and betametasone, shows a pleiotropic behavior on CH235-GM and D54-GM, glioma cell lines. CONCLUSIONS: Inhibition or activation response of Egr-1 promoter shows new framework to explore a mechanism of action of steroid drugs on genetic and epigenetic regulation on tumoral process.