T cell apoptosis pathway

The "T cell apoptosis pathway" is not a single molecule or receptor but rather refers to the collection of molecular mechanisms by which T lymphocytes undergo programmed cell death. This process is essential for immune system homeostasis—eliminating autoreactive thymocytes during development and removing expanded effector T cells after an immune response to prevent autoimmunity and maintain balance[6]. Two major molecular routes mediate this process: 1. **Extrinsic Pathway**: Triggered by engagement of surface "death receptors" such as Fas/CD95 or TNF-related apoptosis-inducing ligand (TRAIL) receptors DR4/DR5. Upon ligand binding, these receptors recruit adaptor proteins like FADD to form the Death-Inducing Signaling Complex (DISC), leading to caspase 8 activation and downstream executioner caspases that dismantle the cell[3][4][7]. 2. **Intrinsic Pathway**: Involves mitochondrial outer membrane permeabilization regulated by Bcl‑2 family proteins; pro-apoptotic signals lead to cytochrome c release and apoptosome formation with APAF1, activating caspase 9 and then effector caspases. In cytotoxic responses, killer T cells can induce target-cell apoptosis through two main mechanisms—perforin/granzyme-mediated entry into target cells triggering intrinsic pathways, or via direct engagement of FasL/Fas on target cells activating extrinsic pathways[1][3]. Therapeutically targeting components of these pathways has been explored in cancer therapy using agents like recombinant TRAIL or agonistic antibodies against its receptors; however, clinical efficacy has been limited due to resistance mechanisms in tumors and pharmacokinetic challenges[5][8]. Because "T cell apoptosis pathway" describes a biological process rather than a discrete druggable entity such as a receptor or enzyme—and encompasses multiple molecules—it is not considered a canonical therapeutic target itself but rather comprises several targets within its network. **Note:** The query refers to an entire cellular signaling cascade ("pathway") rather than an individual molecule/receptor/protein typically catalogued as a drug target. Therefore, *is_incorrect* = true — this entry does not correspond to a specific canonical druggable entity but instead represents an important immunological mechanism involving many potential targets at different nodes within the pathway.[1][3][6]

Other names

T lymphocyte apoptosis pathwayCTL-mediated apoptosisT cell death signaling pathwaysRestimulation-induced cell death (RICD)

Activation of extrinsic apoptotic signaling via death receptors such as Fas and TRAIL receptors[2][3][4][5]