HONG KONG, May 11 -- An AIDS expert said today that he was collaborating with scientists here to design a drug that they hope will control severe acute respiratory syndrome.

David Ho, who helped pioneer treatment for AIDS, said at a news conference that scientists are testing a synthetic protein "inhibitor," or peptide, that is aimed at blocking the SARS virus from penetrating human cells.

The approach used by Ho, who works at the Aaron Diamond AIDS Research Center at Rockefeller University in New York, and scientists from the University of Hong Kong is adapted from a drug that is used in an arsenal of medicines to fight HIV, the virus that causes AIDS.

Ho said the peptide proved successful in preventing the SARS virus from entering cultured cells in initial tests in Hong Kong this week, but more work was needed before a drug could be commercially available. Ho could not give a time frame when that would happen.

Microbiologist Malik Peiris from the University of Hong Kong said some signatures in the SARS virus were similar to the HIV virus.