Advanced Course in Immunology On Demand Lecture Recordings-Effect of the Microbiome on Immunity

Video Transcription

Video Summary

The lecture explains the human microbiome as the collective genomes of microbes living on the skin and mucosal surfaces, especially the gut. The speaker emphasizes that the microbiome contains vastly more genes than the human genome and includes bacteria, fungi, viruses, archaea, and sometimes protozoa and helminths. Major advances in the field came from 16S rRNA sequencing and germ-free mouse models, which revealed that most gut microbes are oxygen-sensitive anaerobes.<br /><br />A key theme is that microbiota vary by body site, age, geography, birth mode, diet, and environment. Vaginal delivery, breastfeeding, fiber-rich diets, and exposure to diverse environments promote a healthier microbiome, while cesarean delivery, formula feeding, antibiotics, processed foods, and industrialized lifestyles can disrupt it. The microbiome helps regulate immunity through metabolites such as short-chain fatty acids, tryptophan derivatives, and bile acids. It also supports colonization resistance, barrier integrity, mucus production, tight junctions, and secretory IgA.<br /><br />The lecture highlights how commensals and pathogens are distinguished by their interactions with the intestinal epithelium, and how microbial products influence T cells, regulatory T cells, Th17 cells, and innate lymphoid cells. The second half focuses on translational efforts, especially food allergy. The speaker’s lab studies how early-life microbiome changes contribute to allergic disease and has tested butyrate-delivering micelles in mice, showing protection against anaphylaxis.<br /><br />Overall, the talk argues that microbiome research is moving from correlation toward causation, with future progress depending on better standardization, mechanistic studies, and targeted therapies.

Asset Subtitle

Lecture 17: Cathryn Nagler, University of Chicago

Effect of the Microbiome on Immunity

Asset Caption

Cathryn Nagler, University of Chicago
Effect of the Microbiome on Immunity

Keywords

human microbiome

gut microbes

16S rRNA sequencing

germ-free mice

anaerobic bacteria

microbiota diversity

short-chain fatty acids

immune regulation

colonization resistance

food allergy

butyrate micelles

anaphylaxis protection