T lymphocytes divide and differentiate when they receive an appropriate activation signal. This signal can be provided by a clonally-distributed, specific antigen receptor (Ti-T3), or through certain broadly distributed cell membrane structures. Molecular biological and in vitro cell culture techniques have been used to investigate the expression of the genes encoding these activation structures, and to study the relationship between structure and function. We have shown using DNA-mediated gene transfer that the clone- specific alpha beta heterodimer completely defines the dual antigen and MHC molecule specificity of mature peripheral T cells. Additional transfection studies have revealed what appears to be a relatively independent contribution of the two V regions of this single receptor to the dual specificity, raising the possibility that the germline repertoire of receptor gene segments is preselected for certain contributions to the ultimate receptor specificity, and that the two chains contribute in a different way to the receptor's recognition potential. Studies of T cell receptor gene expression during ontogeny or T cell maturation in the mature thymus suggest that repertoire selection occurs intra-thymically. These studies also have led to the identification of a new subset of T cell with a distinct receptor termed gamma-delta. Analysis of long term lines of these latter cells shows them to have many of the same effector functions as alpha beta-expressing T cells, but their specificity remains unknown. Investigation of the mechanism of activation of T cells by monoclonal antibodies to non-Ti-T3 surface structures such as Thy-1 revealed a strict dependence on the simultaneous surface expression of Ti-T3. T3- cells could not be stimulated by anti- Thy-1 or Ly6 antibodies, and constitution of T3 expression by gene transfer led to reacquisition of the ability to be stimulated by these antibodies. These studies will enhance our knowledge of which cell membrane molecules are involved in triggering T cells to exert regulatory and effector function, and our understanding of the structural basis for specific T cell responses to antigen.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Intramural Research (Z01)
Project #
1Z01AI000403-05
Application #
3822062
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
5
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Niaid Extramural Activities
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Kastenmuller, Wolfgang; Gasteiger, Georg; Subramanian, Naeha et al. (2011) Regulatory T cells selectively control CD8+ T cell effector pool size via IL-2 restriction. J Immunol 187:3186-97
O'Shea, John J; Hunter, Christopher A; Germain, Ronald N (2008) T cell heterogeneity: firmly fixed, predominantly plastic or merely malleable? Nat Immunol 9:450-3
Germain, Ronald N (2008) Special regulatory T-cell review: A rose by any other name: from suppressor T cells to Tregs, approbation to unbridled enthusiasm. Immunology 123:20-7
Feinerman, Ofer; Germain, Ronald N; Altan-Bonnet, Gregoire (2008) Quantitative challenges in understanding ligand discrimination by alphabeta T cells. Mol Immunol 45:619-31
Altan-Bonnet, Gregoire; Germain, Ronald N (2005) Modeling T cell antigen discrimination based on feedback control of digital ERK responses. PLoS Biol 3:e356
Faure, Sophie; Salazar-Fontana, Laura Ines; Semichon, Monique et al. (2004) ERM proteins regulate cytoskeleton relaxation promoting T cell-APC conjugation. Nat Immunol 5:272-9
Germain, Ronald N (2003) T-cell activation: the power of one. Curr Biol 13:R137-9
Stefanova, Irena; Dorfman, Jeffrey R; Tsukamoto, Makoto et al. (2003) On the role of self-recognition in T cell responses to foreign antigen. Immunol Rev 191:97-106
Germain, Ronald N (2003) Ligand-dependent regulation of T cell development and activation. Immunol Res 27:277-86
Paul, William E; Germain, Ronald N (2003) Obituary: Charles A. Janeway Jr (1943-2003). Nature 423:237

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