Transduction of the rat brain by Bovine Herpesvirus 4

[Bovine herpesvirus 4 (BoHV-4): general aspects of the biology and status in Argentina]

Bovine herpesvirus 4 (BoHV-4) has been isolated from cattle with respiratory infections, vulvovaginitis, mastitis, abortions, endometritis and from apparently healthy animals throughout the world. Although it has not yet been established as causal agent of a specific disease entity, it is primarily associated with reproductive disorders of cattle. This virus can infect a wide range of species, either in vivo or in vitro. Two groups of prototype strains were originated from the first isolates: the DN599-type strains (American group) and the Movar-type strains (European group). In Argentina, BoHV-4 was isolated and characterized in 2007 from vaginal discharge samples taken from cows that had aborted. So far, more than 40 isolates, mainly associated with aborting bovine females have been registered in our country.

In vivo image analysis of BoHV-4-based vector in mice

Due to its biological characteristics bovine herpesvirus 4 (BoHV-4) has been considered as an appropriate gene delivery vector. Its genomic clone, modified as a bacterial artificial chromosome (BAC), is better genetically manipulable and can be used as an efficient gene delivery and vaccine vector. Although a large amount of data have been accumulated in vitro on this specific aspect, the same cannot be asserted for the in vivo condition. Therefore, here we investigated the fate of a recombinant BoHV-4 strain expressing luciferase (BoHV-4-A-CMVlucΔTK) after intraperitoneal or intravenous inoculation in mice, by generating a novel recombinant BoHV-4 expressing luciferase (BoHV-4-A-CMVlucΔTK) and by following the virus replication through in vivo imaging analysis. BoHV-4-A-CMVlucΔTK was first characterized in vitro where it was shown, on one hand that its replication properties are identical to those of the parental virus, and on the other that the transduced/infected cells strongly express luciferase. When BoHV-4-A-CMVlucΔTK was inoculated in mice, either intraperitoneally or intravenously, BoHV-4-A-CMVlucΔTK infection/transduction was exclusively localized to the liver, as detected by in vivo image analysis, and in particular almost exclusively in the hepatocytes, as determined by immuno-histochemistry. These data, that add a new insight on the biology of BoHV-4 in vivo, provide the first indication for the potential use of a BoHV-4-based vector in gene-transfer in the liver.

Herpes simplex virus type 1 thymidine kinase-armed bovine herpesvirus type 4-based vector displays enhanced oncolytic properties in immunocompetent orthotopic syngenic mouse and rat glioma models

Gliomas are devastating tumors of the brain resistant to therapies. Although some therapies can prolong the survival time among the affected persons, gliomas are not curable and new therapeutic approaches need to be investigated. Oncolytic viruses seem to represent an interesting alternative, because anticancer agents and new viral agents have to be explored to identify the one with the best characteristics. Bovine herpesvirus type 4 (BoHV-4) is a gammaherpesvirus with a striking tropism and permissive replication toward cancer cells and rat, mouse, and human glioma cells. However, BoHV-4 does not replicate into the normal brain parenchyma. The BoHV-4 genome was cloned as a bacterial artificial chromosome to easily manipulate this large genome and be used as a viral vector platform. In the present study, a herpes simplex virus type 1 thymidine kinase suicide gene-armed BoHV-4 was constructed, characterized, and proven to be highly efficient in killing by apoptosis glioma cells in vitro when co-administered with the pro-drug ganciclovir (GCV). When the armed BoHV-4/GCV therapeutic approach was tested in immunocompetent orthotopic syngenic mouse and rat glioma models in vivo, a significant increase in survival among the treated animals was achieved, and some animals were completely cured. The BoHV-4-based vector represents a promising alternative oncolytic virus for glioma and, perhaps, other types of cancer treatment that merit further investigation. This article represents the result of a mutual interaction between human medical science and veterinary science, a combination of scientific knowledge often neglected.

Bovine herpesvirus 4 based vector as a potential oncolytic-virus for treatment of glioma

The application of gene therapy for malignant gliomas is still under study and the use of specific vectors represents an important contribution. Here, we investigated bovine herpesvirus 4 (BoHV-4), which is non-pathogenic if injected into the rodent brain. We show that the vector can infect mouse, rat and human glioma cell lines and primary cultures obtained from human glioblastoma in vitro. BoHV-4 was injected into a tumour grown in rat brain. Although virus expression was scattered across the tumour mass, it was mainly located in the peripheral area of larger gliomas. These data support BoHV-4 as a candidate vector for glioma treatment.