Chapter 9 - Antigen-Presenting Cells and T Cell Activation At the end of this topic, students should be able to: . Explain the three-signal model of T cell activation and the source of each signal. . Explain why dendritic cells are the best activators of naïve T cells. . Explain the process of antigen presentation including the interactions between TCR, CD4 or CD8 and the MHC-peptide complex. · Distinguish between professional and non-professional antigen- presenting cells. My office hours will start tomorrow. Thursday afternoon 2 - 3 pm Friday 2:15 - 3:15 pm (changed from what was announced in lecture) Next week will have different hours 1
Chapter 9 - Antigen-Presenting Cells and T Cell Activation Recall the structure of the T cell receptor complex: TCR, co-receptor, CD3 signaling proteins from Chapter 4. TCR a b CD4 : 8 55 -S- CD3 p56lck ?? TCR: recognizes a complex of the MHC and peptide: antigen recognition. CD8 TCR a b CD4 or CD8 co-receptor: strengthens the interaction of the TCR with the MHC-peptide 00 55 -S-S- Å -Å - CD3 and p56lck: signalling CD3 p56lck 2
Chapter 9 - Antigen-Presenting Cells and T Cell Activation The T cell receptor recognizes a combination the MHC protein and the peptide bound in the cleft of the MHC protein. T helper APC T helper cells recognize peptide antigens presented on MHC class II proteins. CTL C APC CTLs recognize peptide antigens presented on MHC class I proteins. 3