Insights into Microbial Pathogenesis and Immunology from Cryptococcus Neoformans

Insights into Microbial Pathogenesis and Immunology from Cryptococcus Neoformans

Air date: Wednesday, January 28, 2015, 3:00:00 PM

Category: WALS - Wednesday Afternoon Lectures

Runtime: 00:59:37

Description: Wednesday Afternoon Lecture Series

The majority of human pathogenic fungi are soil-dwelling microbes that have no obvious need for animal hosts. This raises a fundamental question in microbial pathogenesis: Why do some of these organisms cause disease in mammals? In this lecture we will dissect the biology of the human pathogenic fungus Cryptococcus neoformans in an effort to glean an explanation for the origin of virulence. C. neoformans is an intracellular pathogen with a remarkable replicative strategy that includes the capacity for exciting the host cell without triggering its lysis. This process involves inflicting just enough damage to the host cell to interfere with its microbicidal properties without triggering cell-death pathways such that intracellular replication can proceed unhindered while the host cell remains alive to participate in the exit of fungal cells. The similarity in the interactions between cryptococcal cells with macrophages and amoeba has led to the proposal that the cells' capacity for mammalian virulence emerged accidentally as a result of environmental interactions with phagocytic predators. In this lecture we will also explore the fascinating properties of melanin, an enigmatic pigment that performs a myriad of functions from enhancing cell-wall integrity to energy transduction. We will also consider some of the immunological lessons from studying C. neoformans, which produced important insights into novel antibody protective functions. Finally, we will look at the big picture of fungal pathogenesis and explore the concept of accidental virulence and the likelihood that global warming will bring new fungal diseases.

Author: Arturo Casadevall, M.D., Ph.D., Professor in the Department of Medicine and in the Department of Microbiology and Immunology, Albert Einstein College of Medicine; Chair, Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health