Vancouver (January 20, 2003) - Dr. Philippe Gros and Dr. Silvia Vidal, Investigators of the Canadian Genetic Diseases Network, have identified a gene (Naip5) that makes mice resistant to infection from Legionella bacteria. The study was published in the January 2003 issue of Nature Genetics.

"This study demonstrates that a mouse gene, Naip5, can prevent Legionella infection in mice that would otherwise be susceptible to disease. With this new information, we hope to determine whether human Naip-related genes play a role in the pathogenesis of Legionnaire's Disease (LD) in people", stated Dr. Philippe Gros.

Legionnaire's Disease (LD), a severe form of pneumonia, is caused by infection with Legionella bacteria. Approximately 10-15% of these infections are fatal. The bacteria is typically transmitted to humans through aerosols produced by air conditioning cooling units, showers, and faucets. The first outbreak of LD occurred during a 1976 Legionnaire's Convention in Philadelphia, Pennsylvania.

Gros and his collaborators used a technique called "functional complementation" to identify Naip5. They inserted pieces of mouse chromosome 13 into mice that were susceptible to Legionella infection. When a piece of DNA containing the Naip5 gene was inserted into these same mice, they became resistant to infection. "This shows that in mice Legionella replication is regulated by a host gene and highlights the role of the host's genetic makeup in the infectious process", stated Dr. Silvia Vidal, a co-author in the study, "In the last few years several host genes that provide protection against both viral (e.g. CMV) and bacterial (e.g. mycobacteria) pathogens have been identified. We expect this process will accelerate with the development of better genomic technologies and the availability of the human and mouse genome sequences."

The Naip5 gene was initially identified in a screen for the Spinal Muscular Atrophy gene by Dr. Alex MacKenzie, a CGDN investigator at the Children's Hospital of Eastern Ontario in Ottawa, and important early collaborator in this work. Indeed, the collaboration that led to this breakthrough began when MacKenzie and Gros exchanged ideas at the Network's Annual Scientific Meeting. "This is very exciting. In particular, the seeds for this discovery were made essentially by chance, during the CGDN annual meeting. It is an important step toward the development of innovative treatments for Legionnaire's Disease. It also demonstrates the strength of CGDN's collaborative research program", stated Dr. Michael Hayden, Scientific Director of the Canadian Genetic Diseases Network and Director of the Centre for Molecular Medicine and Therapeutics in Vancouver.

Philippe Gros is a scientist at McGill University Cancer Centre. Silvia Vidal is a scientist at the University of Ottawa. The research was supported with grants from the Canadian Genetic Diseases Network, the Canadian Institutes of Health Research, and Innovation Quebec.

The Canadian Genetic Diseases Network is a not-for-profit corporation, committed to advancing Canada's scientific and commercial competitiveness in genetic research, and the application of genetic discoveries to prevent, diagnose, and treat human disease. To achieve its objectives, CGDN participates in three essential activities: facilitates and funds collaborative research in human genetics across Canada; educates emerging scientists to excel in human genetic disease research; and facilitates partnerships between industry (biotechnology, pharmaceutical, and diagnostic firms) and academia to translate research discoveries into therapies or diagnostic tests.