The Paul Ehrlich and Ludwig Darmstaedter Prize 1999 is awarded to Dr. Robert C. Gallo, Director of the lnstitute of Human Virology at the University of Maryland, Baltimore, USA, for his discovery of human exogenous retroviruses. Gallo will accept the prize, which is endowed with 120,000 DM, on 14 March, Paul Ehrlich's birthday, in the Paulskirche in Frankfurt am Main.

Robert Gallo's research was first recognised when he discovered the messenger substance interleukin 2, which enabled the in vitro cultivation of human T lymphocytes. This led to the discovery of human T-cell leukaemia viruses (HTLV-I and -11), which are responsible for the development of certain forms of leukaemia. They were the first exogenous retroviruses isolated from humans.

This fundamental work enabled him to become one of the discoverers of the causative agent of the immunodeficiency disease AIDS, which is also a retrovirus. In 1984, Robert Gallo was the first to develop a test with which antibodies against the HI virus could be detected in the blood of patients. This simple indirect detection of HIV infections is particularly essential for blood donation because it prevents the transmission of HIV-infected donor blood.

Robert Gallo has also done pioneering work in the field of Kaposi's sarcoma pathogenesis. He also discovered the human herpesvirus 6. Recently, Gallo and his research group were able to detect chemokines that are secreted by CD8+ T lymphocytes, block cellular co-receptors and thus prevent HV infections.

Dr Robert Gallo is a world-renowned virologist and molecular biologist, a leader in the study of the aetiology, pathogenesis and molecular biology of cancer and immunodeficiency-causing viruses. He is both a scientist by training and a licensed physician. After leading the Tumour Cell Biology Laboratory at the US National Cancer Institute for 23 years, Robert Gallo became Director of the new Institute of Human Virology at the University of Maryland in Baltimore in 1995.