One of the central issues in immunology concerns the way in which the immune system is able to discriminate between self and non-self molecules, so that an immune response may be mounted to foreign pathogens while the body's own constituents are tolerated. However, this ability is impaired in some patients and results in auto-immune diseases in which the patients' own tissues are damaged by their immune system. A better understanding of the mechanisms of the tolerance is required to further the basic knowledge of the immune system and to develop insights into how tolerogenic mechanisms break down, leading to a variety of autoimmune conditions. This knowledge may lead to new methods of therapy and prevention of these diseases. The most important cell type upon which tolerance must be imposed is the T lymphocyte which matures in the thymus. Recently, the way in which T cells become tolerant to the antigens present in the thymus has been characterized, but it is not clear how responses to extra-thymic molecules are avoided. Therefore, the primary aim of this proposal is to investigate the mechanisms by which tolerance to self molecules not expressed in the thymus is imposed and maintained. In order to investigate these processes, transgenic mouse models will be used which produce in defined extrathymic sites the class I histocompatibility antigen, H-2Kb. These mice exhibit tolerance in vivo but not in vitro to H-2Kb and present a unique model for investigating tolerance induction. Other transgenic mice will be obtained whose T cells express only H-2Kb receptors, or which produce interleukin-2 in pancreatic Beta cells. The activity, phenotype and date of H-2Kb-reactive T cells will be determined in each of these transgenic mice. The methods required for this work (including production and characterization of transgenic mice, in vitro and in vivo assays of T cell function, skin and thymus grafts, proliferation assays, adult and neonatal thymectomy) have all been successfully used by the applicants.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI029385-02
Application #
3144184
Study Section
Immunobiology Study Section (IMB)
Project Start
1991-04-01
Project End
1994-03-31
Budget Start
1992-04-01
Budget End
1993-03-31
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Walter and Eliza Hall Institute Medical Research
Department
Type
DUNS #
City
Victoria
State
Country
Australia
Zip Code
VIC, -3052
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Allison, J; Stephens, L A; Kay, T W et al. (1998) The threshold for autoimmune T cell killing is influenced by B7-1. Eur J Immunol 28:949-60
Kurts, C; Miller, J F; Subramaniam, R M et al. (1998) Major histocompatibility complex class I-restricted cross-presentation is biased towards high dose antigens and those released during cellular destruction. J Exp Med 188:409-14
Koniaras, C; Heath, W R; Lew, A M (1998) T cell unresponsiveness in vitro can be due to activation in vivo. Int Immunol 10:365-9
Barnden, M J; Allison, J; Heath, W R et al. (1998) Defective TCR expression in transgenic mice constructed using cDNA-based alpha- and beta-chain genes under the control of heterologous regulatory elements. Immunol Cell Biol 76:34-40
Kurts, C; Heath, W R; Kosaka, H et al. (1998) The peripheral deletion of autoreactive CD8+ T cells induced by cross-presentation of self-antigens involves signaling through CD95 (Fas, Apo-1). J Exp Med 188:415-20
Bennett, S R; Carbone, F R; Toy, T et al. (1998) B cells directly tolerize CD8(+) T cells. J Exp Med 188:1977-83
Miller, J F; Heath, W R; Allison, J et al. (1997) T cell tolerance and autoimmunity. Ciba Found Symp 204:159-68; discussion 168-71
Barnden, M J; Heath, W R; Carbone, F R (1997) Down-modulation of CD8 beta-chain in response to an altered peptide ligand enables developing thymocytes to escape negative selection. Cell Immunol 175:111-9
Koniaras, C; Bennett, S R; Carbone, F R et al. (1997) Peptide-induced deletion of CD8 T cells in vivo occurs via apoptosis in situ. Int Immunol 9:1601-5

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