Novel post-translational regulation of TCR expression in CD4 positive CD8 positive thymocytes influenced by CD4

Article Abstract:

It is necessary for T cells to recognize antigens by way of the T cell receptor (TCR) for most immune responses to occur. The production of the TCR on the surface of thymocytes (T cells of the thymus gland) is controlled during development. Immature cells that do not express the proteins CD4 or CD8, and cells that express both CD4 and CD8, produce little or no TCR. When these cells mature and produce one of these proteins, TCR is also manufactured. Regulation of the production of the TCR molecules occurs at the gene level, and the genes coding for TCR must undergo a rearrangement for the proteins to be manufactured. Regulation also occurs at the protein level which involves the transport of TCR to different compartments within the cell. It is thought that a large number of TCRs are degraded, and that only complete and correctly assembled receptors are brought to the surface of the cell. An increase in TCRs occurs if antibodies against CD4 are given to mice. Antibodies against CD4 bind to CD4 on the cell surface and inhibit protein function. The increase in TCR, which is seen on the surface, is not the result of new molecule synthesis, but are molecules from the endoplasmic reticulum, a structure in the cell where these molecules would normally be degraded. Therefore, the CD4 molecule is involved in the control of TCR levels, probably through some type of interaction between the thymocyte and the CD4 molecule. The knowledge of the control of the development and maturation of T cells is important in understanding and manipulating the immune system to fight off diseases. (Consumer Summary produced by Reliance Medical Information, Inc.)

Cell receptors, Immune system, CD8 lymphocytes

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Structure of the complex between human T-cell receptor, viral peptide and HLA-A2

Article Abstract:

The structure of a complex of human T-cell receptor (TCR), viral Tax peptide and a major histocompatibility complex (MHC) molecule HLA-A2 contains diagonal binding of TCR. Variable loops in the TCR structure bury a majority of the peptide and MHC molecule. The diagonal orientation and binding mode of TCR is similar to that observed in all general class I and class II molecules. Orientation of the loops, their interaction with Tax and HLA-A2, and TCR's signalling and specificity are discussed.

Analysis, Peptides, T cell antigen receptors, Major histocompatibility complex, Chemical structure

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• Abstracts: Class II MHC molecules can use the endogenous pathway of antigen presentation. part 2 Defective processing and presentation of exogenous antigens in mutants with normal HLA class II genes

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