The Department has completed an unprecedented period of expansion: we have more than tripled our number in the past three years, with the incoming faculty active in newly constructed or renovated laboratories. Our new members include immunologists, molecular biologists, virologists, microbiologists, and computational biologists who work in functional and computational microbial genomics and in host-pathogen relationships, including the immune response to pathogens from its most fundamental aspects to the science of immunization. In addition, we have opened three major new core facilities that serve the College community: for microarray analysis of gene expression and polymorphism/mutation profiling; for computational genomics; and for wet-bench and animal work with pathogens at the biologic safety level 3.

The Department's Program in Persistent Infections directs attention to a particularly complex set of host-pathogen relationships. Mycobacteria, the human immunodeficiency virus and the malaria-causing plasmodia are the three leading causes of death from infectious disease. They are each models of persistent infections, some of whose other causative agents are major contributing factors to malignancies, gastrointestinal ulcers, cirrhosis, and perhaps atherosclerotic cardiovascular disease. Such infections involve fundamental issues of immune recognition and regulation over long periods of time. Antigenic variation directs attention to genomic instability in the pathogens, and inflammatory tissue damage can elicit mutagenesis in the host. Prolonged periods of latency involve issues of cell cycle control in prokaryotes that remain to be explored. Vaccination against persistently infecting pathogens poses a particularly demanding intellectual challenge while promising enormous potential rewards including what is surely the leading opportunity to use the immune system against cancer.

Studies of genomic regulation and host-pathogen interactions come together in their implications for gene therapy, including mechanisms for regulating gene integration and expression, control of the immune response to vectors, and use of the immune response for targeted gene delivery. Indeed, vaccination with DNA may be one of gene therapy's most promising avenues.