A cytotoxic (or TC) T cell is a T cell (a type of white blood cell) which has on its surface antigen receptors that can bind to fragments of antigens displayed by the Class I MHC molecules of virus (or other intracellular pathogen) infected somatic cells and tumor cells. T cells are a subset of lymphocytes that play a large role in the immune response. ... White Blood Cells redirects here. ... An antigen is a molecule that stimulates the production of antibodies. ... It has been suggested that Class I MHC be merged into this article or section. ... The term somatic refers to the body. ...
Once activated by a MHC-antigen complex, TC cells release the cytoxins perforin and granulysin, which forms pores in the target cell's plasma membrane; this causes ions and water to flow into the target cell, making it expand and eventually lyse. TC also release granzyme, a serine protease, that can enter target cells via the perforin-formed pore and induce apoptosis (cell death). Perforin is a cytolytic protein found in the granules of CD8 T-cells and NK cells. ... A pore, in general, is some form of opening, usually very small. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Lysis (Greek lusis from luein = to separate) is the reduction of symptoms of a disease the dissolving of cells osmotic lysis chemical lysis viral lysis a dialogue of Plato about friendship (philia) This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same... Granzymes are exogenous serine proteases that are released by cytoplasmic granules within cytotoxic T cells and natural killer cells. ... In biochemistry, serine proteases or serine endopeptidases (newer name) are a class of peptidases (enzymes that cleave peptide bonds in proteins) that are characterised by the presence of a serine residue in the active center of the enzyme. ... Apoptosis In biology, apoptosis (from the Greek words apo = from and ptosis = falling, commonly pronounced ap-a-tow-sis[1]) is one of the main types of programmed cell death (PCD). ...
A second way to induce apoptosis is through an interaction between cell-surface molecules on the TC and the infected cell. When a TC is activated it starts to express the surface cytokine FAS ligand, which can bind to Fas molecules on the target cell. This Fas-Fas ligand interaction is the main route to dispose of unwanted T lymphocytes during their development. The FAS ligand is a type II transmembrane protein that belongs to the tumor necrosis factor (TNF) family. ... T cells are a subset of lymphocytes that play a large role in the immune response. ...
Most TC cells have the protein CD8 present on the cell surface, which is attracted to portions of the Class I MHC molecule. This affinity keeps the TC cell and the target cell bound closely together during antigen-specific activation. TC cells with CD8 surface protein are called CD8+ T cells. CD8 (cluster of differentiation 8) is a molecule that is expressed on the surface of cytotoxic T cells. ...
CytotoxicTcells are activated when their TCR binds to an MHC class I molecule presenting viral antigen, which can occur on any nucleated or neoplastic cell.
cells release the cytoxins perforin and granulysin, which forms pores in the target cell's plasma membrane; this causes ions and water to flow into the target cell, making it expand and eventually lyse.
cells have the proteinCD8 present on the cell surface, which is attracted to portions of the Class I MHC molecule.
CytotoxicTcells are a key part of the cellular immune response, killing cells that display foreign antigen on their surface, primarily virus-infected cells.
CytotoxicTcells also express Fas ligand to bind to Fas on target cells and induce apoptosis.
CytotoxicTcell activation also requires additional signals provided by helperTcells in addition to signals provided by antigen-presenting cells.
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