Dutch biotechnology company Crucell N.V. has discovered a monoclonal antibody for protection against West Nile virus. Study results have demonstrated that the fully human monoclonal antibody, derived from patients who survived West Nile infection, effectively neutralized the virus in cell culture and fully protected mice from an otherwise lethal infection.

While the vaccine will be targeted at preventing infection in the elderly population most at risk of developing the most severe form of the disease, the antibody may be applied post-infection in specific cases to prevent the potentially fatal onset of encephalitis.

Crucell's chief scientific officer Jaap Goudsmit says, "West Nile virus continues to cause serious annual epidemics in the United States and elsewhere. While our determined efforts to develop a vaccine continue, an antibody may provide another route to prophylaxis, providing passive immunity in the event of an outbreak, and possibly therapy for patients who might otherwise develop encephalitis."

The discovery of the West Nile antibody follows the Group's discovery of antibodies against SARS and Rabies during 2004. It also complements Crucell's West Nile virus vaccine development program that is due to enter clinical trials at the end of 2005.

Since its emergence in New York in 1999, West Nile virus has spread throughout the entire United States. Health authorities in the US now view the disease as a recurring threat, surfacing every summer with warm and humid weather.