Portnoy received a B.A. in bacteriology from UCLA in 1978 and a Ph.D. in 1983 under the tutelage of Stanley Falkow at the University of Washington and Stanford. He conducted postdoctoral research at the Rockefeller University working with Jay Unkeless and Jeff Ravetch. Next, at Washington University and then the University of Pennsylvania, he began working on Listeria monocytogenes as a model intracellular pathogen and that research continues to the present. In 1997, Portnoy moved to UC Berkeley where he currently holds joint appointments in Molecular and Cell Biology and Plant and Microbial Biology. Portnoy teaches an upper division undergraduate course on bacterial pathogenesis and is the PI on a P01 entitled, Intracellular pathogens and innate immunity. Portnoy’s contributions were recognized by his election to the National Academy of Sciences in 2013 and the National Academy of Inventors in 2017.

Research Interests

The Portnoy lab tackles a wide range of problems related to the pathogenesis and host response to intracellular pathogens with the goal of developing vaccines and therapeutics. Specifically, the lab works on Listeria monocytogenes, a facultative intracellular food-borne bacterial pathogen that is an outstanding model system with which to dissect basic aspects of host-pathogen interactions. The lab is focused on the interaction of the facultative intracellular bacterial pathogen Listeria monocytogenes and its mammalian host. This fascinating microorganism is able to enter cells, escape from a phagosome, circumvent autophagy, avoid cell death pathways, and grow rapidly in the cytosol. By exploiting a host system of actin-based motility, the bacteria move through the cytosol to the cell membrane and into pseudopod-like projections (listeriopods) that are ingested by neighboring cells. This mechanism allows pathogens to spread from one cell to another without ever leaving the host cytoplasm thereby avoiding the immune response. Current research covers many topics including basic microbiology, the cell biology of infection, innate immune responses, acquired immunity, and vaccine development to both infectious diseases and cancer.

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Primary Section

Section 44: Microbial Biology