The thymus and T cell development: a primer

Published on April 3, 2022   39 min

Other Talks in the Series: The Immune System - Key Concepts and Questions

Other Talks in the Series: Periodic Reports: Advances in Clinical Interventions and Research Platforms

Please wait while the transcript is being prepared...
Hello and welcome to this presentation. My name is George Holländer. I am a professor at the University of Oxford in the United Kingdom, with affiliations to the ETH Zürich and the University of Basel, both in Switzerland. We are talking today about the thymus and T cell development, and the presentation is a primer into this topic.
The thymus is the primary T lymphoid organ and sits in the chest cavity in front of the heart. It's anatomical location is between the two pulmonary lobes. If analysed by histology, it will reveal a lobulated structure where each of the lobules has a cell dense outer cortex and a central medulla that appears to be less packed with lymphoid cells.
What is the overall function of the thymus? The thymus is similar to an Institute of Higher Education. Where precursor cells - shown as the students - enter the institute or the university. After a while, they will successfully exit as fully trained individuals. During their time at the university, they are being taught to achieve certain functional capacities. The teachers - shown as the individuals with the yellow coats - have a particular task for the students to achieve. Namely the creation of a graduation cap that fulfils certain criteria. In biological terms, the students are the developing T cells, and the graduation cap is a T-cell antigen receptor that conforms to certain qualitative criteria. Now, as you can see some of the students are well on their way and have chosen mortars that don't conform to the overall expectation of the square. Now, in particular, there is a student in the middle that is being told off by the teacher and sent away in shame. What happens to this example, but obviously not in real life, is this student will await a very drastic outcome and will eventually be deleted from the classroom. This is really the fate of most of the T cells that are being educated in the thymus. The overall goal of the immune system is