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Reading Assignment: Janeway et al. Chapter 3 pp 115-131 and Chapter 5 and Appendix I pp 706-707 or Parham Chapter 3 and Chapter 2 Fig. 2.13.
Supplementary Materials: MHC, TCR , Flow Cytometry Optional reading: Ober, C. et al. HLA and mate choice in humans. Amer J Human Gen 61: 497-50
T Cell Receptor (TCR) is the specific protein that T cells use to recognize antigen. Antigen molecules binding to TCR molecules on naïve or memory T cells deliver signals that initiate activation of the cells to effector T cells (cytotoxic or helper T cells). Most TCR only bind antigen peptides that are presented on Major Histocompatibility Complex Class I or Class II (MHC I or MHC II) proteins on the membranes of infected calls or professional antigen-presenting cells (APC).
Cytotoxic T cells (Tc) recognize (bind) cytosolic pathogens presented on Class I MHC of infected cells and then kill those infected cells. In addition to TCR that binds antigen peptide + MHC I, cytotoxic T cells have membrane CD8 that binds to MHC I.
Helper T cells (Th) recognize phagocytosed extracellular (vesicular) pathogens presented on Class II MHC of professional antigen presenting cells and then signal the APC to produce antibodies (B cells) or kill phagocytosed pathogen (macrophages). In addition to TCR that binds antigen peptide plus MHC II, helper T cells have membrane CD4 that binds to MHC II. This unit describes the structure of TCR and MHC, as well as the pathways of antigen processing and presentation by virus-infected cells and professional antigen presenting cells (APC = dendritic cells, macrophages and B cells).
http://microvet.arizona.edu/Courses/MIC419/LearningObjectives/LOAgProcPres.html
Written by Janet M. Decker, PhD jdecker@u.arizona.edu
Last modified
February 5, 2007