Antibody Kills West Nile Virus in Mice

This finding was reported in the May 2005 issue of Nature Medicine.

A single dose of the antibody administered soon after infection was shown to boost survival rates to 90% and higher in a strain of mice that normally has only about a 10% survival following infection by WNV. The disease varies in its effects on humans. Some people infected with the virus have no symptoms at all or only a mild flu-like illness. In others, the virus invades the central nervous system and causes paralysis or coma.

Scientists at Washington University School of Medicine (St. Louis, MO, USA) decided to develop the antibody treatment after finding that antibodies taken from the blood of people who recovered from WNV could cure mice infected with the virus. However, antibodies derived from human blood have potential disadvantages: they vary in their ability to fight the disease and, although all precautions are taken to purify the antibodies, the blood might harbor other dangerous infectious agents.

The researchers made 46 monoclonal antibodies against WNV and then eliminated the less-effective ones through a molecular-level screening process. They then turned to MacroGenics, Inc. (Rockville, MD, USA), to create a human-like version of the most effective antibody. This monoclonal antibody was several hundred times more potent in cell culture tests than antibodies obtained from people who had recovered from WNV infection.

"We could give this antibody to mice as long as five days after infection, when West Nile virus had entered the brain, and it could still cure them [the mice],” observed Michael Diamond, M.D., Ph.D., an assistant professor of molecular microbiology at Washington University School of Medicine and head of the research team. "To our knowledge, these experiments are the first successful demonstration of the use of a humanized antibody as a post-exposure therapy against a viral disease.”






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