AIRR-C Seminar Series, November 30, 2023 - Julien Limenitakis, University of Bern, Switzerland
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Diet and Microbiota effects on
Diet and Microbiota effects on the B cell repertoire
Early Career Speaker: Julien Limenitakis, University of Bern, Switzerland
Talk abstract
Colonization by the microbiota causes a marked stimulation of B cells and induction of immunoglobulin, but mammals colonized with many taxa have highly complex and individualized immunoglobulin repertoires. To study this, we opted for a simplified model of defined transient exposures to different microbial taxa in germ-free mice to deconstruct how the microbiota shapes the B cell pool and its functional responsiveness. We previously showed that microbial exposure at the intestinal mucosa generated oligoclonal responses that differed from those in germ-free mice, and from the diverse repertoire that was generated after intravenous systemic exposure to microbiota. Our results reflected a contrast between a flexible response to systemic exposure with the need to avoid fatal sepsis, and a restricted response to mucosal exposure that reflects the generic nature of host–microbial mutualism in the mucosa. A hallmark of mucosal IgA is the high mutational load that accumulates throughout life. This has been mainly interpreted in terms of differences in microbial induction, although once established in early life, the microbiome of humans and experimental mice is relatively stable and mutational activity has been shown to be independent of B cell receptor signaling. Using germ-free and colonized mice provided with different diets formulated with proprietary grain-based processing or from purified chemicals with different principal macronutrient calorie sources, we show that diet affects IgA induction, its repertoire and mutational diversification independently of microbial exposure.
Speaker Bio
Dr. Julien Limenitakis received his PhD in Microbiology from the University of Geneva. He then joined the Mucosal Immunology group of Andrew Macpherson with a transitional Post-doctoral fellowship from the Swiss Systems Biology Initiative, switching fields to apply systems biology approaches and computational methods to study interactions of gut microbes with the immune system. Currently he is a senior scientist at the University Hospital Bern. His work focuses on how exposure to intestinal microbes, in particular during early life development, shapes B-cell repertoires.
AIRR-C Seminar Series website: https://www.antibodysociety.org/the-a...
Early Career Speaker: Julien Limenitakis, University of Bern, Switzerland
Talk abstract
Colonization by the microbiota causes a marked stimulation of B cells and induction of immunoglobulin, but mammals colonized with many taxa have highly complex and individualized immunoglobulin repertoires. To study this, we opted for a simplified model of defined transient exposures to different microbial taxa in germ-free mice to deconstruct how the microbiota shapes the B cell pool and its functional responsiveness. We previously showed that microbial exposure at the intestinal mucosa generated oligoclonal responses that differed from those in germ-free mice, and from the diverse repertoire that was generated after intravenous systemic exposure to microbiota. Our results reflected a contrast between a flexible response to systemic exposure with the need to avoid fatal sepsis, and a restricted response to mucosal exposure that reflects the generic nature of host–microbial mutualism in the mucosa. A hallmark of mucosal IgA is the high mutational load that accumulates throughout life. This has been mainly interpreted in terms of differences in microbial induction, although once established in early life, the microbiome of humans and experimental mice is relatively stable and mutational activity has been shown to be independent of B cell receptor signaling. Using germ-free and colonized mice provided with different diets formulated with proprietary grain-based processing or from purified chemicals with different principal macronutrient calorie sources, we show that diet affects IgA induction, its repertoire and mutational diversification independently of microbial exposure.
Speaker Bio
Dr. Julien Limenitakis received his PhD in Microbiology from the University of Geneva. He then joined the Mucosal Immunology group of Andrew Macpherson with a transitional Post-doctoral fellowship from the Swiss Systems Biology Initiative, switching fields to apply systems biology approaches and computational methods to study interactions of gut microbes with the immune system. Currently he is a senior scientist at the University Hospital Bern. His work focuses on how exposure to intestinal microbes, in particular during early life development, shapes B-cell repertoires.
AIRR-C Seminar Series website: https://www.antibodysociety.org/the-a...
7 ماه پیش
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