EXCEED THE SPACE PROVIDED. The specificity of the T cell recognition process is determined by the nature of interactions between the T cell receptor (TCR) and its ligand, peptide-MHC (pMHC) complex. For MHC class I restricted responses, the coreceptor CD8 provides co-stimulatory signals and has the potential to modulate the T cell response during thymic development and T cell activation. However, the precise role played by CD8 during TCR binding to pMHC (peptide-MHC) ligands is not clearly defined. It is not clear whether CD8 has a direct influence on TCR-pMHC binding, or its effect is purely due to enhanced signal transduction, or both. It has been proposed that CD8 might interact only with TCR-pMHC complexes that are relatively long-lived. Alternatively, CD8 might interact directly during TCR-pMHC complex formation, and consequently modulate TCR-pMHC interactions. It is reasonable to believe that co-stimulatory signals would be most effective and advantageous in enhancing low affinity TCR-pMHC interactions as in the case of weak agonist or positive selecting ligands. To address these issues, we propose to use a novel BIAcore binding assay to quantitate TCR-pMHC, CD8-MHC, and CD8-MHC-TCR trimolecular interactions on membranes expressing intact TCR and coreceptors. This technique will allow us to study the interactions between :hese molecules under conditions where TCR and co-receptors are expressed in their native -onformations and environment.
The specific aims of the project are: (1) to measure the binding kinetics and affinity of the interactions between membrane associated intact TCR-CD3 (mTCR) and peptide-MHC (pMHC) complexes; (2) to study the influence of CD8 on ligand specific binding of mTCR to pMHC complexes; (3) to define the thermodynamics of TCR binding to pMHC complex and the influence of coreceptor CD8; and (4) to study the influence of glycosylation on the binding of TCR and CD8. The kinetic and thermodynamic characterization of CD8 molecule as a modulator of TCR-pMHC interactions can serve as a basis for understanding immunomodulation of T cell responses, particularly against _athogens that elicit low avidity cytotoxic T lymphocyte (CTL). PERFORMANCE SITE ========================================Section End===========================================

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI053232-03
Application #
6843782
Study Section
Allergy and Immunology Study Section (ALY)
Program Officer
Nabavi, Nasrin N
Project Start
2003-09-30
Project End
2007-01-31
Budget Start
2005-02-01
Budget End
2007-01-31
Support Year
3
Fiscal Year
2005
Total Cost
$346,500
Indirect Cost
Name
Duke University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Lam, Yee; Abu-Lail, Nehal I; Alam, Munir S et al. (2006) Using microcantilever deflection to detect HIV-1 envelope glycoprotein gp120. Nanomedicine 2:222-9