Michael A. Fischbach, Ph.D. Associate Professor, Department of Bioengineering,
Department of Microbiology & Immunology, Stanford University
This lecture is part of “Microbiomes,” the 2023 lecture series theme in biology. Microscopic lifeforms live just about everywhere on Earth — in the deep ocean, suspended in the atmosphere and even in our planet’s interior. Microbial communities can even thrive within plants and animals, affecting the biology and biochemistry inside their hosts. On the environmental scale, microbial communities profoundly impact food chains, biogeochemical cycling and climate. This series of talks will explore microbiomes and their roles in specific hosts and environments.
2023 Lecture Series Themes
Neuroscience and Autism Science: The Neuroscience of Sleep
Physics: The Third Quantum Revolution
Mathematics and Computer Science: Waves
Simons Foundation Presidential Lectures are free public colloquia centered on four main themes: Biology, Physics, Mathematics and Computer Science, and Neuroscience and Autism Science. These curated, high-level scientific talks feature leading scientists and mathematicians and are intended to foster discourse and drive discovery among the broader NYC-area research community. We invite those interested in the topic to join us for this weekly lecture series.
Many microbial species colonize animals, with some species benefiting from their hosts without causing any harm. Some of these ‘commensal’ members of the microbiome can elicit a potent T cell response from their host’s immune system upon colonization.
In this talk, Michael Fischbach will describe two recent projects by his research group that aim to characterize and manipulate anti-commensal immune responses.
In the first project, he and his colleagues explored the functional properties of colonist-induced T cells by engineering the skin bacterium Staphylococcus epidermidis to express tumor antigens anchored to secreted or cell-surface proteins. Upon colonization, the engineered S. epidermidis elicited tumor-specific T cells that circulated, infiltrated local and metastatic lesions, and exerted cytotoxic activity. Their findings show that the immune response to a colonist can be redirected against a target of therapeutic interest by expressing a target-derived antigen in a commensal.
In the second project, they colonized germ-free mice with a complex defined community (made up of more than 100 bacterial strains) and profiled T cell responses to each strain individually. They found that T cell recognition of Firmicutes bacteria was focused on a widely conserved cell-surface antigen, opening the door to new therapeutic strategies in which colonist-specific immune responses are rationally altered or redirected.