Cobra venom helps hybrid virus evade immune response and repeatedly attack tumours

March 24, 2017

Viruses have shown promise in treating cancer, but it can be challenging to get multiple doses to a tumour because our immune system quickly learns to recognize and attack viruses. Two of our main antiviral defenses include antibodies that attach to viruses and prevent them from spreading and complement molecules that punch holes in them.

Dr. John Bell and his colleagues have found a way for cancer-fighting viruses to avoid both of these defenses. Their approach makes use of the lymphocytic choriomeningitis virus, which has a unique ability to evade antibodies. It also uses the Maraba MG1 virus, which attacks many cancer cells without harming normal cells, as well as a protein from cobra venom that blocks complement molecules.

When they made a genetic hybrid of the two viruses and combined it with the cobra venom protein, they found that they could get 135 times more virus into tumours in laboratory models than when using the original Maraba on its own.

See Molecular Therapy – Oncolytics for details.

The Maraba MG1 virus is being tested in clinical trials in Canada. See our answers to frequently asked questions from patients.

Co-authors: Laura Evgin, Carolina S Ilkow, Marie-Claude Bourgeois-Daigneault, Christiano Tanese de Souza, Lawton Stubbert, Michael S Huh, Victoria A Jennings, Monique Marguerie, Sergio A Acuna, Brian A Keller, Charles Lefebvre, Theresa Falls, Fabrice Le Boeuf, Rebecca A Auer, John D Lambris, J Andrea McCart, David F Stojdl, and John C Bell.

Funders: The Terry Fox Research Institute, the Ontario Institute for Cancer Research, The Ottawa Hospital Foundation, the Ottawa Regional Cancer Foundation, the Ontario Institute for Cancer Research, National Institutes of Health, Canadian Institutes for Health Research, the European Community’s Seventh Framework Programme.

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