SAN FRANCISCO, FEBRUARY 11: US Government scientists have discovered a new way that HIV attacks human cells, an advance that could provide fresh avenues for the development of additional therapies to stop AIDS, they reported on Sunday. The discovery is the identification of a new human receptor for HIV. The receptor helps guide the virus to the gut after it gains entry to the body, where it begins its relentless attack on the immune system. The findings were reported online Sunday in the journal Nature Immunology by a team headed by Dr Anthony S Fauci, the director of the National Institute of Allergy and Infectious Diseases. For years, scientists have known that HIV rapidly invades the lymph nodes and lymph tissues that are abundant throughout the gut, or intestines. The gut becomes the prime site for replication of HIV, and the virus then goes on to deplete the lymph tissue of the key CD4 HIV-fighting immune cells. That situation occurs in all HIV-infected individuals, however they may have acquired the infection. The findings appear to provide some, if not the main, answers to how and why that situation occurs. Dr Warner C. Greene, an AIDS expert and the director of the Gladstone Institute of Virology and Immunology here who was not involved in the research, said the findings were "an important advance in the field.'