Target type: biologicalprocess
The change in morphology and behavior of a mature or immature T cell resulting from exposure to an antigen for which its T cell receptor is specific bound to an MHC molecule on an antigen presenting cell, leading to the initiation or perpetuation of an immune response. [GOC:add, ISBN:0781735149]
T cell activation is a complex process that initiates an immune response upon encountering an antigen. The process begins when a T cell receptor (TCR) on the surface of a T cell recognizes and binds to an antigen presented by an MHC molecule on an antigen-presenting cell (APC). This interaction is highly specific, ensuring that T cells only respond to relevant threats.
The TCR is a heterodimer composed of alpha and beta chains, each containing variable regions that determine antigen specificity. The MHC molecule is a transmembrane protein that presents peptide fragments of antigens to T cells. There are two main classes of MHC molecules: MHC class I presents peptides derived from intracellular proteins, while MHC class II presents peptides derived from extracellular proteins.
Upon TCR binding to an antigen-MHC complex, the TCR initiates a signaling cascade that leads to T cell activation. This cascade involves a series of intracellular events, including phosphorylation of signaling molecules, activation of transcription factors, and gene expression changes.
Several co-receptors contribute to T cell activation. CD4+ T cells recognize antigens presented by MHC class II molecules, while CD8+ T cells recognize antigens presented by MHC class I molecules. These co-receptors amplify the TCR signal and contribute to T cell differentiation into specific effector cells.
Following activation, T cells undergo a process called clonal expansion, where they proliferate and differentiate into effector T cells. These effector cells are specialized to eliminate the antigen.
The overall process of T cell activation can be summarized as follows:
1. **Antigen presentation:** An APC captures an antigen, processes it, and presents it on its surface in association with an MHC molecule.
2. **TCR recognition:** A T cell with a TCR specific for the presented antigen recognizes and binds to the antigen-MHC complex.
3. **Signal transduction:** The TCR-mediated recognition triggers a signaling cascade within the T cell, leading to activation.
4. **T cell activation:** Activation results in clonal expansion and differentiation of T cells into effector T cells.
5. **Effector function:** Effector T cells eliminate the antigen and mediate immune responses.
This complex process ensures that T cells specifically target relevant antigens while avoiding autoimmune responses.'
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Protein | Definition | Taxonomy |
---|---|---|
Integrin alpha-L | An integrin alpha-L that is encoded in the genome of human. [PRO:CNA, UniProtKB:P20701] | Homo sapiens (human) |
Intercellular adhesion molecule 1 | An intercellular adhesion molecule 1 that is encoded in the genome of human. [PRO:WCB, UniProtKB:P05362] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
indole | indole; polycyclic heteroarene | Escherichia coli metabolite | |
1,4-benzodioxan | 1,4-benzodioxan: structure in first source | ||
1-methylindole | 1-methylindole: SKATOLE refers to 3-methylindole; RN given refers to parent cpd; structure methylindole : Any member of the class of indoles carrying one or more methyl substituents. | ||
lovastatin | lovastatin : A fatty acid ester that is mevastatin carrying an additional methyl group on the carbobicyclic skeleton. It is used in as an anticholesteremic drug and has been found in fungal species such as Aspergillus terreus and Pleurotus ostreatus (oyster mushroom). Lovastatin: A fungal metabolite isolated from cultures of Aspergillus terreus. The compound is a potent anticholesteremic agent. It inhibits 3-hydroxy-3-methylglutaryl coenzyme A reductase (HYDROXYMETHYLGLUTARYL COA REDUCTASES), which is the rate-limiting enzyme in cholesterol biosynthesis. It also stimulates the production of low-density lipoprotein receptors in the liver. | delta-lactone; fatty acid ester; hexahydronaphthalenes; polyketide; statin (naturally occurring) | anticholesteremic drug; antineoplastic agent; Aspergillus metabolite; prodrug |
chlorfenethazine | chlorfenethazine: RN given refers to parent cpd; synonym elroquil refers to HCl; structure | phenothiazines | |
2-bromohippuric acid | |||
cucurbitacin r | 23,24-dihydrocucurbitacin D : A 23,24-dihydrocucurbitacin in which a lanostane skeleton is multi-substituted with hydroxy, methyl and oxo substituents, with unsaturation at position 5. cucurbitacin R: from Cayaponia tayuya roots; structure in first source | 23,24-dihydrocucurbitacin; secondary alpha-hydroxy ketone; tertiary alpha-hydroxy ketone | |
benzotript | benzotript: anti-gastrinic; active group is amide; structure | ||
cucurbitacin d | cucurbitacin D : A cucurbitacin in which a lanostane skeleton is multi-substituted with hydroxy, methyl and oxo substituents, with unsaturation at positions 5 and 23. cucurbitacin D: toxic constituent in edible gourd; see also records for cucurbitacins & specific cucurbitacins | cucurbitacin; secondary alpha-hydroxy ketone; tertiary alpha-hydroxy ketone | |
nsc 106399 | cucurbitacin E : A cucurbitacin in which a lanostane skeleton is multi-substituted with hydroxy, methyl and oxo substituents, with unsaturation at positions 1, 5 and 23. cucurbitacin E: RN refers to (9beta,10alpha,16alpha,23E)-isomer; structure given in first source | cucurbitacin; tertiary alpha-hydroxy ketone | |
cucurbitacin i | cucurbitacin I : A cucurbitacin that is 9,10,14-trimethyl-4,9-cyclo-9,10-secocholesta-2,5,23-triene substituted by hydroxy groups at positions 2, 16, 20 and 25 and oxo groups at positions 1, 11 and 22. cucurbitacin I: toxic constituent in edible gourd; see also records for cucurbitacins & specific cucurbitacins | cucurbitacin; tertiary alpha-hydroxy ketone | antineoplastic agent; plant metabolite |
pd 144795 | |||
birt 377 | |||
4-[(4-methylphenyl)thio]-2-thieno[2,3-c]pyridinecarboxamide | aryl sulfide | ||
a 286982 | A 286982: inhibits the interaction between leukocyte function-associated antigen-1 and intracellular adhesion molecule-1; structure in first source | ||
bio 1211 | BIO 1211: integrin alpha4beta1 inhibitor; structure in first source | ||
sar 1118 | lifitegrast : An N-acyl-L-alpha-amino acid obtained by formal condensation of the carboxy group of N-[2-(1-benzofuran-6-carbonyl)]-5,7-dichloro-1,2,3,4-tetrahydroisoquinoline-6-carboxylic acid with the amino group of 3-(methanesulfonyl)-L-phenylalanine. Used for treatment of keratoconjunctivitis sicca (dry eye syndrome). lifitegrast: An LFA-1 (LYMPHOCYTE FUNCTION-ASSOCIATED ANTIGEN-1) antagonist that is used in the treatment of DRY EYE SYNDROMES. | 1-benzofurans; isoquinolines; L-phenylalanine derivative; N-acyl-L-alpha-amino acid; sulfone | anti-inflammatory drug; lymphocyte function-associated antigen-1 antagonist |