Download presentation
Presentation is loading. Please wait.
1
Principles of Immunology T Cell Receptors 3/9/06 “Education is a better safeguard of liberty than a standing army.” Edward Everett
2
Word/Terms List CD3 CDR Heterodimer Homodimer ITAM TCR Complex
3
Study of TCRs Early studies of Ag response B cells/Ab TCRs as an Ig/ IgT
4
Comparing BCRs vs. TCRs BCRs Soluble Ags Non MHC restricted TCRs Membrane bound Ags MHC restricted (self) Both are Ag specific
6
TCR and BCR Structural Comparison BCR “Dimer of dimers” (two heterodimers) Two dimers of one heavy/one light Varying number of domains. For IgG 4 and 2 ;IgM 5 and 2 Constant and variable domains Bivalent for Ag binding CDRs in Fab
7
TCR and BCR Structural Comparison TCR Heterodimer One alpha/one beta Two domains each Constant and variable domains Monovalent for Ag Hypervariable regions in V domains
9
TCR Complex Includes the TCR plus CD3 CD3 Contains six chains One homodimer Two different heterodimers Has many ITAMs Function? Significance? Essential for TCR expression and post Ag recognition signal transduction Intra membrane oppositely charged residues
12
Two Types of TCRs Predominantly alpha/beta Also see gamma/delta Gamma/delta TCR cells are less discriminating Respond to phospholipid Ags May be “first responders”
14
TCR Genetic Diversity TCR gene expression Seen in T cells only Alpha chain encoded by V and J segments (~ to Ig light chains) Beta chain encoded by V, D and J segments (~ to Ig heavy chains) Combinatorial joining occurs resulting in at least 3 million combinations No somatic mutation contributing to diversity
16
TCR Accessory Molecules Act as co-receptors CD4 Monomer; four domains CD8 Heterodimer; one domain each CD2 Each accessory molecule reacts with a ligand on the APC or target cell
20
TCR Binding vs. BCR Binding TCR binding with Ag Less specific than BCR Less tightly bound But more adhesion molecules Greater number of ITAMs
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.