Receptor T-cell

The TCR is composed of integral membrane protein that recognizes the antigen and as a consequence its activation produces an immune response to eliminate the antigen. This process results in the development of CD4+ or CD8+ cells from the precursor T cells. It involves other cell surface receptors and downstream signal transduction mechanisms. 

The TCR is a member of the immunoglobulin superfamily and is composed of an N-terminal immunoglobulin variable domain, an immunoglobulin constant 

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Percus J K, Percus O E and Perelson A S 1993 Predicting the size of the T-cell receptor and antibody combining region from consideration of efficient self-nonself discrimination Proc. Natl Acad. Sci. USA 90 1691-5... 

Figure 15.19 Schematic representation of the peptide-binding domain of a class I MHC protein. The al and a2 domains are viewed from the top of the molecule, showing the empty antigen-binding site as well as the surface that is contacted by a T-cell receptor. (Adapted from P.J. Bjdrkman et al.. Nature 329 506-512, 1987.)...

T-cell receptors have variable and constant immunoglobulin domains and hypervariable regions... 

T-cell receptors (TCR) are heterodimeric transmembrane glycoproteins found exclusively in T cells, with extracellular domains that closely resemble antibody Fab structures. Each of the TCR a and p chains forms half of an extracellular antigen-binding domain, and in addition has one transmembrane... 

Figure 15.21 T-cell receptor cx and p genes undergo rearrangments much like immunoglobln genes (see Figure 15.5).

Figure 15.22 T-cell receptor stucture shown as a ribbon diagram. The anbgen-binding site is formed by CDR loops (labeled 1 to 3) from the Va and Vp domain, as for antibodies.

To date, there has not been a reported structure determination of a class 11 MHC-peptide-TCR complex. However, T-cell receptors that recognize class... 

Fremont, D.H., Rees, W.A., Kozono, H. Biophysical studies of T-cell receptors and their ligands. Curr. Opin. Struct. Immunol. 8 93-100, 1996. 

Wilson, I.A., Garcia, K.C. T-cell receptor structure and TCR complexes. Curr. Opin. Struct. Biol. 7 839-848, 1997. 

Wang, J., et al. Atomic structure of an ap T-cell receptor (TCR) heterodimer in complex with an anti-TCR Fab fragment derived from a mitogenic antibody. EMBO J. 17 10-26, 1988. 

AMPK can also be activated by a Ca2+-mediated pathway involving phosphorylation at Thr-172 by the Ca2+/calmodulin-dependent protein kinase, CaMKK 3. CaMKKa and CaMKK 3 were discovered as the upstream kinase for the calmodulin-dependent protein kinases-1 and -IV they both activate AMPK in a Ca2+/ calmodulin-dependent manner in cell-free assays, although CaMKK 3 appears to much more active against AMPK in intact cells. Expression of CaMKKa and CaMKK(3 primarily occurs in neural tissues, but CaMKKp is also expressed in some other cell types. Thus, the Ca2+-mediated pathway for AMPK activation has now been shown to occur in response to depolarization in rat neuronal tissue, in response to thrombin (acting via a Gq-coupled receptor) in endothelial cells, and in response to activation of the T cell receptor in T cells. 

COPD is a chronic inflammatory disease that results from prolonged and repeated inhalation of particles and gases, chronic (or latent) infection or an interaction of these factors. In many cases, the inflammation persists even when the exposure (in most cases smoking) is stopped. Prominent among the infiltrating leukocytes are neutrophils, CD8+ lymphocytes (Co-receptor for the T-cell receptor. CD8+ is specific for the class IMHC protein. It is expressed on the surface of cytotoxic T-cells and natural killer cells.) and CD68+ monocytic cells (A lysosomal antigen. All cells that rich in... 

Immune Defense T Cell Receptors Rheumatoid Arthritis... 

Inhibition of immunomodulatory cytokines (Fig. 1) Anti-T-cell receptor antibodies Muromonab (OKT3, Orthoclone ) binds to the CD3 complex of the T-cell receptor and induces depletion of T-lymphocytes. It is applied to prevent acute rejection of kidney, liver, and heart allografts. Rapid side effects (within 30-60 min) include a cytokine release syndrome with fever, flu-like symptoms, and shock. Late side effects include an increased risk of viral and bacterial infections and an increased incidence of lymphproliferative diseases due to immunosuppression. 

Cytokines. Figure 1 Inhibition of cytokine synthesis during activation of the specific immune system. The monoclonal antibodies Muromonab and Basiliximab are specific for the CD3 complex of the T-cell receptor, and for the IL-2 receptor on lymphocytes, respectively. Cyclosporin and Tacrolimus inhibit activation of cytoplasmic NF-AT, a transcription factor essential for activation of the IL-2 gene ( NFAT Family of Transcription Factors). Sirolimus interferes with mTOR signaling and inhibits IL-2 dependent proliferation. Red pharmaka, blue target proteins. 

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