New research shows that HIV targets a receptor that helps establish viral replication especially in the gut. Scientists have for years known HIV quickly invades the abundant lymph nodes and lymph tissue in the intestines. No matter how the virus was acquired, the gut becomes the major site of HIV replication as it depletes the lymph tissue's HIV-fighting CD4 lymphocytes.
The study found that HIV targets a receptor, the molecule integrin alpha-4 beta-7, which directs immune cells to the intestines. A protein on the outer shell of HIV adheres to a molecule in integrin alpha-4 beta-7 that is tied to the way CD4 cells home in on the gut, said the researchers, who were led by Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases. HIV's binding to integrin alpha-4 beta-7 triggers another molecule, LFA-1, which plays a key role in HIV's spread from cell to cell. These actions eventually lead to HIV's destruction of lymph tissue, especially in the gut.
"The work we did took nearly two years, and there's little doubt that what we have found is a new receptor," said Fauci, adding that "we certainly have to learn a lot more about it." Hopefully, he said, the findings will help scientists study new ways to fight HIV.
For example, experimental drugs that block the receptor are being studied for the treatment of autoimmune disorders. New trials could soon test their safety and efficacy against HIV, Fauci said.
The full study, "HIV-1 Envelope Protein Binds to and Signals Through Integrin Alpha-4 Beta-7, the Gut Mucosal Homing Receptor for Peripheral T-Cells," was published online Sunday in Nature Immunology (2008;doi:10.1038/ni1566).
02/11/08
UNITED STATES: Scientists Find New Receptor for HIV
Source: http://www.nytimes.com/ ::Lawrence K. Altman; Courtesy of the CDC National Center for HIV, STD, and TB Prevention