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by Rachel Patzer, News Reporter

The first high-resolution image of the West Nile virus was recently produced by a group of scientists at Purdue University who hope the new picture of the pathogen will lead to better medicines and treatment.

Researchers Dr. Richard J. Kuhn and colleagues published their method and results in the current journal Science. Purdue scientists cooled the tiny virus to a temperature of negative 300 degrees Fahrenheit in liquid ethane and then deflected high-energy electrons off the virus to produce an image.

Because of its small size, just one five hundred-thousandth of an inch wide, the image of the virus was difficult to obtain.

Information obtained from the structure of the virus could help scientists determine the function of the infecting cells of the virus and the disease caused in the host.

“Our structure shows what the mature virus looks like. This gives us some ideas on how it puts itself together,” Kuhn said.

The information on the structure also holds potential for the development of vaccines.

“Vaccines can be developed to stimulate immune responses against the most relevant proteins of a virus,” said University of Wisconsin Assistant Professor of Immunology M. Suresh. “The data in the paper suggest that vaccines which stimulate antibodies against the E protein, or envelope protein, may provide protective immunity.”

West Nile virus is different than typical viruses because the envelope protein that forms the exterior surface of the viral particle lays flat against the membrane, rather than forming a spike, said UW Professor of Animal Health and Biomedical Sciences Geoff Letchworth.

The shapes of the viral proteins determine which types of cells in the human body the virus can permeate. A virus typically consists of DNA or RNA enclosed in a protective coating or envelope made of proteins.

Viruses do not contain self-replicating devices and must use a host cell to reproduce.

The West Nile virus first appeared in the U.S. in 1999 and has rapidly extended across the country. This year, 7,021 people have already been infected, and 152 have died from the virus.

“Immediate experiments will test these assembly models on how [the mature virus] puts itself together,” Kuhn said.

According to Letchworth, it is the envelope protein that attaches to cells, allowing the virus to plant an infection. Antibodies can bind to the surface and “neutralize” the virus, inhibiting an infection.

While researchers hope to find vaccines against the West Nile virus, there may be several drawbacks to consider. Because the envelope proteins of the West Nile virus are unique, vaccines may be difficult to make. If the conformation of the envelope protein is wrong, the human body cannot produce the correct antibody — a vaccine must mimic the correct conformation of the envelope protein.

“In order for the vaccine to work, the envelope protein has to be in the same shape, or conformation, as on the virus surface. This allows your body to make antibodies that bind to the conformation present on the virus,” Letchworth said. “The same group who just published the West Nile virus work showed previously that the envelope proteins change dramatically under some conditions.”