First identified more than 20 years ago at UCLA, defensins arepeptides naturally produced by the immune system to ward off viruses.However, it was unclear how defensins worked. Now UCLA and NIHscientists have discovered that a specific defensin calledretrocyclin-2 (RC2) binds to carbohydrate-containing proteins in cellmembranes. This mechanism erects molecular barricades that blockattacking viruses from entering and infecting the cell. RC2 stops thevirus in its tracks, preventing it from replicating and spreadingthroughout the body.
The NIH/UCLA team used human and animal cell lines todemonstrate RC2's protection against the influenza virus. The team'searlier studies suggest that RC2 offers great promise as the leadcompound for new antiviral drugs to fight off HIV and herpes, as well.Unlike antibodies, however, defensins are not pathogen specific. Inaddition to blocking viruses, RC2 also kills several bacteria that arehighly resistant to conventional antibiotics.
Authors of the study include Dr. Robert Lehrer, DistinguishedProfessor of Medicine at the David Geffen School of Medicine at UCLA,and Leonid Chernomordik, Ph.D., section chief of Membrane Biology,Laboratory of Cellular and Molecular Biophysics, who led the NIH team.
FUNDING: The National Institute of Child Health and HumanDevelopment and NIH's Intramural Research Program supported theresearch. The W.M. Keck Foundation established the UCLA FunctionalProteomics Center, which also participated in the study.
JOURNAL: The Sept. 11 online edition of Nature Immunology publishes the research. A PDF of the manuscript is available upon request.
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