Guests: Dr. Robert Doms Assistant Professor of Pathology and Laboratory Medicine University of Pennsylvania Philadelphia, Pennsylvania Dr. H. Clifford Lane Clinical Director National Institute of Allergy and Infectious Diseases National Institutes of Health Bethesda, Maryland Dr. Robert Gallo Professor and Director Institute of Human Virology University of Maryland Baltimore, Maryland This week, articles in two scientific journals report that certain molecules may block some of the receptors needed for HIV infection. This could translate into new ways to treat or prevent AIDS infection. This comes after news that the number of new AIDS cases diagnosed in the U.S. has dropped for the first time since the discovery of the disease, and that the number of AIDS deaths in this country dropped 23 per cent from 1995 to 1996. But while there may be cause for optimism, there is still a long way to go. Join Ira Flatow in this hour of Science Friday for an AIDS update.