T cell mediated cytotoxicity

Definition

Target type: biologicalprocess

The directed killing of a target cell by a T cell through the release of granules containing cytotoxic mediators or through the engagement of death receptors. [GOC:add, GOC:pr, ISBN:0781735149, PMID:11911826]

T cell-mediated cytotoxicity is a critical mechanism of the adaptive immune system that eliminates infected, cancerous, or damaged cells. It involves a complex series of steps initiated by the recognition of specific antigens presented on the surface of target cells by T cell receptors (TCRs) expressed on cytotoxic T lymphocytes (CTLs). This recognition event triggers a cascade of intracellular signaling events that ultimately lead to the release of cytotoxic molecules, primarily granzyme B and perforin, by the CTL.

Granzyme B is a serine protease that enters the target cell via perforin-formed pores. Perforin, a pore-forming protein, facilitates the delivery of granzyme B into the cytoplasm of the target cell. Once inside the target cell, granzyme B activates a caspase cascade, a series of proteases that ultimately lead to the activation of the apoptotic pathway, causing programmed cell death.

Furthermore, CTLs can also express the Fas ligand (FasL) on their surface. Upon activation, FasL interacts with its receptor, Fas, on the surface of the target cell. This interaction activates the death receptor pathway, also leading to apoptosis.

In summary, T cell-mediated cytotoxicity involves the recognition of specific antigens, activation of intracellular signaling pathways, release of cytotoxic molecules, and induction of apoptosis in the target cell. This intricate process is essential for maintaining immune homeostasis and eliminating threats to the host organism.'
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Proteins (6)

Compounds (55)