Arturo

Casadevall

,

MD

Perhaps the most important medical advance in history was the reduction in deaths by infectious diseases in the 20th century. This resulted from improved sanitation, the development of many vaccines and the introduction of antibiotics. Unfortunately, the last two decades have witnessed a return of infectious diseases as a major contributor to death and illness. The causes include the emergence of new pathogens (disease-causing agents), the spread of resistant organisms, medical progress that predisposes to infection, and the HIV pandemic. Also, medical researchers are realizing that many organisms can be engineered as biological weapons, providing a new specter for terrorism. These two phenomena have heightened the resurgence of research in microbes (disease-causing microorganisms) and the means by which they cause disease. Furthermore, it is now apparent that all healthy humans have a complex microbial flora that regulates many of the physiological process of the body and contributes to both wellness and disease. These changes, together with tremendous advances in immunology and molecular biology have launched a new golden age of microbiological research. Dr. Arturo Casadevall is a microbiologist and immunologist. His laboratory studies two fundamental questions: First, how do microbes cause disease? Second, how do hosts, such as humans, protect themselves against microbes? To address these large questions, the laboratory has a multidisciplinary research program spanning several areas of basic immunology and microbiology. A major focus of the laboratory is the fungus Cryptococcus neoformans, a ubiquitous environmental microbe that is a frequent cause of disease in individuals with impaired immunity. The fungus causes lung infection, including a particularly dangerous fungal meningitis observed primarily in immune-compromised patients such as those with AIDS. Many of the laboratory’s projects seek to understand how hosts defend against C. neoformans and how the Cryptococcus organism’s virulence contributes to disease. For example, melanin production in C. neoformans, is associated with virulence. Melanin is a pigment with an undefined chemical structure and tremendous physical stability. This pigment accumulates in the cell wall of C. neoformans and allows growth and budding to occur. But melanin research also has wide reach: an antibody to fungal melanin made in the Casadevall laboratory is currently in evaluation for the treatment of melanoma, a type of skin cancer. In recent years the laboratory has also worked with other microorganisms including Bacillus anthracis, a bacterium that causes anthrax and is a major agent of biological warfare because it produces spores that can be easily dispersed. The laboratory is interested in devising antibody-based countermeasures to protect against anthrax.