Tumorigenic poxviruses: growth factors in a viral context?

Madin-Darby bovine kidney (MDBK) cells are a suitable cell line for the propagation and study of the bovine poxvirus lumpy skin disease virus

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LSDV replicates to high titers (approximately 1 × 10⁷ PFU/mL) in MDBK cells.

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LSDV forms foci-like poxviral plaques in MDBK cells.

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A plaque-reduction neutralisation test was developed for LSDV antibody quantitation.

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A method for purification of LSDV genomic DNA was optimized.

Lumpy skin disease virus (LSDV) is a poxvirus that causes systemic disease in cattle, resulting in substantial economic loss to affected communities. LSDV is a rapidly emerging pathogen of growing global concern that recently spread from Africa and the Middle East into Europe and Asia, impacting the cattle population in these regions. An increase in research efforts into LSDV is required to address key knowledge gaps, however this is hampered by lack of suitable cell lines on which to propagate and study the virus. In this work we describe the replication and spread of LSDV on Madin-Darby bovine kidney (MDBK) cells, and the formation of foci-type poxvirus plaques by LSDV on MDBK cells. Methods utilising MDBK cells to quantify neutralising antibodies to LSDV, and to purify LSDV genomic DNA suitable for short read sequencing are described. These research methods broaden the tools available for LSDV researchers and will facilitate the gathering of evidence to underpin the development of LSD control and prevention programmes.

Viral exploitation of the MEK/ERK pathway - A tale of vaccinia virus and other viruses

The VACV replication cycle is remarkable in the sense that it is performed entirely in the cytoplasmic compartment of vertebrate cells, due to its capability to encode enzymes required either for regulating the macromolecular precursor pool or the biosynthetic processes. Although remarkable, this gene repertoire is not sufficient to confer the status of a free-living microorganism to the virus, and, consequently, the virus relies heavily on the host to successfully generate its progeny. During the complex virus-host interaction, viruses must deal not only with the host pathways to accomplish their temporal demands but also with pathways that counteract viral infection, including the inflammatory, innate and acquired immune responses. This review focuses on VACV and other DNA or RNA viruses that stimulate the MEK (MAPK - Mitogen Activated Protein Kinase)/ERK- Extracellular signal-Regulated Kinase) pathway as part of their replication cycle.

DNA-tumor virus entry--from plasma membrane to the nucleus

DNA-tumor viruses comprise enveloped and non-enveloped agents that cause malignancies in a large variety of cell types and tissues by interfering with cell cycle control and immortalization. Those DNA-tumor viruses that replicate in the nucleus use cellular mechanisms to transport their genome and newly synthesized viral proteins into the nucleus. This requires cytoplasmic transport and nuclear import of their genome. Agents that employ this strategy include adenoviruses, hepadnaviruses, herpesviruses, and likely also papillomaviruses, and polyomaviruses, but not poxviruses which replicate in the cytoplasm. Here, we discuss how DNA-tumor viruses enter cells, take advantage of cytoplasmic transport, and import their DNA genome through the nuclear pore complex into the nucleus. Remarkably, nuclear import of incoming genomes does not necessarily follow the same pathways used by the structural proteins of the viruses during the replication and assembly phases of the viral life cycle. Understanding the mechanisms of DNA nuclear import can identify new pathways of cell regulation and anti-viral therapies.

Fighting cancer with oncolytic viruses

Although gene therapy has huge potential for modern medicine, our enthusiasm for its powerful potential must not cloud our judgment about the dangers of using increasingly diverse, yet relatively untested, replicating viruses