During the past year, there have been two areas of research ongoing in the Molecular Immunology Section: 1) identification of structure/function relationships of human CD8+ T cell antigen-specific receptors (TCR) and 2) determination of differential gene expression in CNS lesions of MS patients. Structural analysis of TCR recognition has been examined using T cell assays, kinetic and thermodynamic binding assays, and X-ray crystallography. The emphasis on these studies has been on the mechanism of how TCRs that are specific for multiple peptides presented by HLA-A2 actually bind to the HLA-A2 molecule. The overall conclusion is that there are conserved amino acids on the alpha one (K66) and alpha two (Q155) helices of the HLA-A2 molecule that are key anchor residues that are recognized by most HLA-A2-restricted TCRs. For most HLA-A2/peptide complexes whose structures have been solved, the side chains of these key amino acids also contact the bound peptide. These findings demonstrate that the molcular mechanism underlying MHC restriction is that the TCR/MHC interaction cannot be physically separated from the peptide/MHC interaction because key elements of the MHC molecule not only are directly contacted by the TCR but these same MHC elements also contribute to the conformation of the bound peptide. Analysis of differential gene overexpression in CNS lesions of MS patients and the brains of mice with EAE by cDNA microarray technology has been performed by monitoring the expression pattern of over 2800 genes known or suspected to be involved in immune responses. Four genes were found to be overexpressed in each of 18 MS lesions examined and in the brains of two strains of mice with EAE compared to normal white mattter. The product of one of these genes, 5-Lipoxygenase (5-LO), was found in the lesions of four different MS patients but not in normal white matter by immunohistochemistry. Since 5-LO is the enzyme crucial for the biosynthesis of inflammatory leukotrienes, this previously unreported proinflammatory enzyme in MS lesions may contribute to pathology, and provide a new opportunity for therapeutic intervention. Thus, cDNA microarray technology represents a powerful new tool for the identification of genes not previously associated with the MS disease process.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Intramural Research (Z01)
Project #
1Z01NS002603-19
Application #
6675675
Study Section
(MIS)
Project Start
Project End
Budget Start
Budget End
Support Year
19
Fiscal Year
2002
Total Cost
Indirect Cost
City
State
Country
United States
Zip Code
Gagnon, Susan J; Borbulevych, Oleg Y; Davis-Harrison, Rebecca L et al. (2006) T cell receptor recognition via cooperative conformational plasticity. J Mol Biol 363:228-43
Gagnon, Susan J; Turner, Richard V; Shiue, Michael G et al. (2006) Extensive T cell receptor cross-reactivity on structurally diverse haptenated peptides presented by HLA-A2. Mol Immunol 43:346-56
Gagnon, Susan J; Borbulevych, Oleg Y; Davis-Harrison, Rebecca L et al. (2005) Unraveling a hotspot for TCR recognition on HLA-A2: evidence against the existence of peptide-independent TCR binding determinants. J Mol Biol 353:556-73
Niland, Brian; Banki, Katalin; Biddison, William E et al. (2005) CD8+ T cell-mediated HLA-A*0201-restricted cytotoxicity to transaldolase peptide 168-176 in patients with multiple sclerosis. J Immunol 175:8365-78
Baxter, Tiffany K; Gagnon, Susan J; Davis-Harrison, Rebecca L et al. (2004) Strategic mutations in the class I major histocompatibility complex HLA-A2 independently affect both peptide binding and T cell receptor recognition. J Biol Chem 279:29175-84
Tomaru, Utano; Yamano, Yoshihisa; Nagai, Masahiro et al. (2003) Detection of virus-specific T cells and CD8+ T-cell epitopes by acquisition of peptide-HLA-GFP complexes: analysis of T-cell phenotype and function in chronic viral infections. Nat Med 9:469-76
Buslepp, Jennifer; Wang, Huanchen; Biddison, William E et al. (2003) A correlation between TCR Valpha docking on MHC and CD8 dependence: implications for T cell selection. Immunity 19:595-606
Gagnon, Susan J; Wang, Zichun; Turner, Richard et al. (2003) MHC recognition by hapten-specific HLA-A2-restricted CD8+ CTL. J Immunol 171:2233-41
Stefanova, Irena; Hemmer, Bernhard; Vergelli, Marco et al. (2003) TCR ligand discrimination is enforced by competing ERK positive and SHP-1 negative feedback pathways. Nat Immunol 4:248-54
Biddison, William E; Turner, Richard V; Gagnon, Susan J et al. (2003) Tax and M1 peptide/HLA-A2-specific Fabs and T cell receptors recognize nonidentical structural features on peptide/HLA-A2 complexes. J Immunol 171:3064-74

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