"This marks one of the few successful in vivo, or in-animal, models of an effective therapy to reduce the production of hepatitis B virus," said Gary Clawson, M.D., Ph.D., professor of pathology, biochemistry and molecular biology, Penn State College of Medicine. "Although this work focused on hepatitis B virus, our method of targeting and packaging ribozymes should also be applicable to the development of therapies to fight other viruses."

The study was published March 5 in the online version of the journal, Molecular Therapy, the official journal of the American Society of Gene Therapy, and will appear in the journal's April print edition.

Hepatitis B virus (HBV) attacks the liver and can cause lifelong infection, liver cancer and, eventually, death. Although HBV is treated with drugs, it cannot be cured. The chronic disease affects about 1.25 million Americans, 20 percent to 30 percent of whom acquired the virus in childhood. HBV is transmitted via blood or sexual activity, but also may be transmitted from mother to child during childbirth. Once infected, the virus continues to reproduce in the liver.

Clawson, who is also director of the Jake Gittlen Cancer Research Center at Penn State Milton S. Hershey Medical Center, and his team developed the SNIPAA cassette, which contains a double-dose of a special type of ribozyme called a trans-acting hammerhead ribozyme. Ribozymes are ribonucleic acid (RNA) segments that, like enzymes, cause chemical changes or splitting in other RNA segments. RNA, which is critical to the replication of DNA - life's instruction book - also is critical to the replication of viruses. The SNIPAA cassette was packaged in liposomes, typical vehicles for delivering drugs in the body, and the liposomes in turn were modified with pr
'"/>

Contact: Valerie Gliem
vgliem@psu.edu
814-865-9481
Penn State
22-Mar-2004