David D. Ho, M.D.

David Ho is the Irene Diamond Professor at The Rockefeller University and the Scientific Director and CEO of the Aaron Diamond AIDS Research Center. The Ho group pioneered the first life-extending treatments for HIV, using quantitative analyses to model the dynamics of viral infection and predict optimal combinations of antiviral drugs that were tested in patients at The Rockefeller University Hospital. The Ho group also helped to identify the central molecular gateway HIV uses to infect T cells, providing targets for drug discovery. Their newest work includes:

• Development of candidate vaccines to protect against HIV infection. Preparations are under way for a clinical trial in China.
• Intensive study of the earliest stages of HIV infection—work that is critical to vaccine and drug development.

Ralph M. Steinman, M.D.

Ralph Steinman, the Henry G. Kunkel Professor at The Rockefeller University, directs the Christopher H. Browne Center for Immunology and Immune Diseases. Dr. Steinman discovered the dendritic cell, which plays an essential role in alerting T cells to the presence of invading microbes. The Steinman laboratory is now learning to harness the immune stimulating features of dendritic cells in the design of HIV vaccines. He and his colleagues are enhancing the delivery of vaccines directly to dendritic cells in the body's immune organs. This in turn leads to stronger immune responses to HIV. In addition, the Steinman lab is investigating:

• Tolerance, a natural mechanism of the immune system that HIV exploits to "silence" immunity — the opposite of what is required for effective vaccination. Tolerance is mediated by dendritic cells.
• Use of specially treated dendritic cells to boost immunity against HIV in individuals who are already infected.