A team led by Professor David Ho, director of Aaron Diamond AIDS Research Center in New York and a native of China, published their findings in the latest issue of the journal Science.

Since 1986, scientists have known that CD8 T cells in the immune systems of certain HIV-infected patients can produce certain substance which somehow suppresses the virus' replication, possibly preventing the viral infection from progressing into AIDS. But identity of the substance remained a mystery.

Using protein-chip technology, Ho and his colleagues have now identified that three proteins called alpha-defensins fit the description of the substance.

Their study showed that synthetic forms of these proteins can inhibit the replication of various forms of HIV viruses in cell cultures.

The discovery "is a major step forward" in understanding how the body fights HIV and may explain why some people infected with the HIV virus live significantly longer without ever developing aids, the researchers said.

However, they stressed that more work is still necessary to determine how potent the proteins are in the body, and to figure out exactly how they might be useful for treating HIV.

( September 27, 2002)