7_ T-CELL DEVELOPMENT & T-CELL ACTIVATION.pptx

WELCOME! BMS 545 IMMUNOLOGY OCTOBER 2, 2024  OBJECTIVES (ON-GOING, THIS & NEXT CLASS)  Describe the microenvironments of the thymus where each stage of T-cell development takes place  Describe the changes in expression of CD4, CD8, and TCR that occur during T-cell development  Compare &...

WELCOME! BMS 545 IMMUNOLOGY OCTOBER 2, 2024  OBJECTIVES (ON-GOING, THIS & NEXT CLASS)  Describe the microenvironments of the thymus where each stage of T-cell development takes place  Describe the changes in expression of CD4, CD8, and TCR that occur during T-cell development  Compare & contrast αβ and δγ cells (& start familiarizing yourself with how they are similar/different to B1 & B2 cells- more of a focus next module)  Define and describe the importance of, and the basis for, positive and negative selection.  Articulate the relationship between positive selection and MHC restriction, as well as the relationship between negative selection and central tolerance  Recognize the variety of T cells that are generated in the thymus and articulate a basic understanding of the events that lead to the development of each lineage, particularly the CD4+, CD8+ and δγ! Figure 7.15 The early development of αβ T cells in the thymus THYMOCYTES DEVELOP IN THE THYMUS  For mature, antigen-recognizing T cells to develop without being self- reactive, T cells must go through both positive & negative selection  Positive selection- thymocytes that bind self-MHC/peptides in the cortex with intermediate affinity are selected to mature, migrating to the medulla for negative selection  Negative selection- Thymocytes whose T Cell Receptors (TCRs) bind self-MHC/peptide complexes with too-high affinity are induced to die (apoptosis) 