Scientists describe genetic resistance to rampant virus

Montreal, QC – Researchers at McGill University Health Centre have defined genetic resistance to the widespread virus, cytomegalovirus (CMV) – a member of the viral group that causes some of the world’s most prevalent diseases, such as herpes, chicken pox and mononucleosis.

The research, published in Nature Genetics last week, provides a roadmap for the development of human therapies for CMV, which could prolong the life of HIV patients and improve the success of transplant surgery by reducing the risk of rejection. There is currently no treatment or cure for CMV.

Resistance to diseases like CMV depends, at least partially, on the ability of our body’s defense mechanism to recognize and destroy them. “Detecting these pathogens is not always easy,” says Dr Silvia Vidal, a Canada research chair in host response to virus infection based at the centre and lead author of the new research. “CMV has developed cunning disguises to avoid detection by our natural killer cells – one of several cell types that hunt down and terminate unwelcome invaders within our body.”

Dr Vidal and her team have spent the past 10 years studying CMV-resistant mouse strains in an attempt to describe the nature of their genetic resistance. “This research marks our second discovery of genetic resistance to CMV,” she says. Most significantly, this new research documents an entirely new mechanism of resistance to CMV, involving the interaction between two genes. One gene flags virus-infected cells for destruction, the other gene allows our natural killers cells to recognize and terminate them. “This is a new concept in natural disease resistance,” notes Dr Vidal. “Our research suggests there are many different mechanisms for fighting viruses; in the future we expect to discover additional resistant genotypes.”

CMV infects most of the world’s organisms, including upwards of 80% of the human population. Although healthy people suffer only mild symptoms, infection can trigger fatal reactions in those with a compromised immune system, such as organ transplant recipients, newborns and persons infected with HIV. Dr Vidal believes her groundbreaking discovery increases the likelihood that therapies will be developed to fight CMV.