Limit of T cell tolerance to self proteins by peptide presentation

Article Abstract:

In a fundamental sense, the entire function of the immune system is based on the distinction between self and non-self antigens. At least part of the tolerance of the immune system for self antigens arises early in development, when self-reactive T-cells are eliminated from the repertoire during the differentiation of the thymus. However, not all specific self-reactive T cells are eliminated, but this is not a problem if the T-cells are reactive to specific self antigens which, under normal circumstances, are present in densities too small to elicit a response. In experiments with immune cells from mice, it has been shown that when self proteins are artificially prepared and added to self cells, in concentrations which are higher than those normally occurring, a cytotoxic T-cell response may be demonstrated. This demonstrates that not all possible self-reacting T-cells are deleted in early development. The self-reactive cells evident in these experiments do not react with normal mouse cells; nevertheless, the experiments may reflect on the mechanisms of autoimmune diseases. It may be possible for some pathologic conditions to result in unnaturally high concentrations of some antigens. Under these conditions, an autoimmune reaction may occur. There is some evidence that increased concentrations of a shock protein occurring during a mycobacterial infection may induce a cytotoxic T-cell reaction, which results in tissue damage. (Consumer Summary produced by Reliance Medical Information, Inc.)

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Mechanisms of immunological tolerance

Article Abstract:

The body's immune system can distinguish foreign substances from self, or nonforeign substances, and when healthy, will respond to the foreign substances. Recent data have shown that the mechanism of immunological tolerance or the lack of activity against self is due to the elimination of certain T cells, a subset of lymphocytes, during development, that would react with self. The destruction of these autoreactive clones of cells occurs in the thymus, a gland where T cells mature. Recent studies by Hodes et al. and Fry et al. in the Nov 24, 1989 issue of Science confirm that autoreactive clones are eliminated in the thymus. They show that a strain of mice that do not have thymus glands do not eliminate autoreactive clones. Some cells that develop into autoreactive clones seem to escape destruction either because they do not go to the thymus or because the thymus does not recognize the T cells as self antigens. These cells can expand into clones and can cause autoimmune disease, where the body reacts with its own cells or tissues.

Models, Physiological aspects, Autoimmune diseases, Thymus, Thymus gland, column

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Control of Neonatal Tolerance to Tissue Antigens by Peripheral T Cell Trafficking

Article Abstract:

The results from a research and study conducted by scientists on th eimmune system is given. The report focused on the tolerance induction at the neonatal and adult stages. Research on T-cells and their functions are noted with findings recorded and explained.

Scientists

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