Scientists at Jefferson Medical College may have helped devise a new way to fight the hepatitis B virus (HBV). Timothy Block, Ph.D., professor of biochemistry and molecular pharmacology and medicine at Thomas Jefferson University in Philadelphia, and his colleagues at several institutions have found that by interfering with a specific step in the life cycle of the woodchuck hepatitis virus, the virus can't reproduce, shutting down its ability to infect a cell.

By blocking the creation of a virus "envelope", the virus DNA is locked within the infected cell. As a result, levels of the virus in the animals' bloodstream drop dramatically. The researchers say that the work may provide leads to improved methods of fighting hepatitis B virus (HBV) and hepatitis C (HCV) infections in chronically infected humans.

"This points to a new way to inhibit the hepatitis B virus," says Dr. Block, who is a member of Jefferson's Kimmel Cancer Center and director of the Jefferson Center for Biomedical Research and Agricultural Medicine. Dr. Block and his colleagues report their results in May in the journal Nature Medicine.

"We've discovered that a very specific step in the life cycle of the virus that can be selectively inhibited by a drug, N-nonyl-DNJ," he explains. "It works by inhibiting the first step in the glycosylation process that all cell glycoproteins go through to reproduce and be able to infect. We discovered that the host cellular glycoproteins appear to be far less sensitive to this inhibition than is HBV.

"We were able to inhibit this step in glyco-processing and shut down the appearance of infectious virus in most of the infected animals," he says. "It prevents the appearance of envelope virus in the animals' blood, so it prevents infection.

"This paper introduces another way of inhibiting HBV," he says. "The other ways to inh
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Contact: Steve Benowitz
steven.benowitz@mail.tju.edu
215-955-6300
Thomas Jefferson University
27-Apr-1998