Target type: biologicalprocess
Any process that activates or increases the frequency, rate or extent of T cell costimulation. [GOC:obol]
Positive regulation of T cell costimulation is a crucial biological process that fine-tunes the activation and differentiation of T lymphocytes, ensuring appropriate immune responses. It involves a complex interplay of molecules expressed on the surface of T cells and antigen-presenting cells (APCs). Here's a detailed breakdown:
1. **Initial Activation:** T cell activation begins when the T cell receptor (TCR) on a T cell engages with its specific antigen presented by an MHC molecule on an APC. This initial interaction, while necessary, is not sufficient for full T cell activation.
2. **Costimulatory Signals:** To fully activate a T cell, additional signals, known as costimulatory signals, are required. These signals are delivered through interactions between costimulatory molecules expressed on both the T cell and the APC.
3. **CD28 and B7 Family:** The most well-characterized costimulatory pathway involves the interaction of CD28 on the T cell with its ligands B7.1 (CD80) and B7.2 (CD86) on the APC. This interaction provides a critical second signal that amplifies TCR signaling and promotes T cell survival, proliferation, and differentiation.
4. **Other Costimulatory Molecules:** Several other costimulatory molecules contribute to the regulation of T cell activation, including:
* **CD40-CD40L:** This interaction promotes APC activation and cytokine production, further enhancing T cell responses.
* **ICOS-ICOSL:** ICOS engagement on T cells promotes T cell survival and cytokine production, particularly Th2 cytokine production.
* **CTLA-4:** This molecule acts as a negative regulator of T cell activation by competing with CD28 for B7 binding, dampening T cell responses and preventing excessive inflammation.
5. **Regulation of Immune Responses:** Positive regulation of T cell costimulation ensures that T cells are only activated in the presence of an appropriate antigen and costimulatory signals, preventing inappropriate or excessive immune responses. It fine-tunes the magnitude and duration of T cell activation, promoting effective immune responses while minimizing collateral damage.
6. **Immune Dysregulation:** Dysregulation of costimulatory pathways can contribute to various immune disorders, including autoimmunity, allergies, and cancer.
In summary, positive regulation of T cell costimulation is a tightly regulated process that plays a critical role in shaping the immune response by ensuring appropriate T cell activation and differentiation.'
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Protein | Definition | Taxonomy |
---|---|---|
C-C chemokine receptor type 7 | A C-C chemokine receptor type 7 that is encoded in the genome of human. [PRO:WCB, UniProtKB:P32248] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
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tak 779 | |||
cenicriviroc | cenicriviroc : A member of the class of benzazocines that is (5Z)-1,2,3,4-tetrahydro-1-benzazocine which is substituted by a 2-methylpropyl, N-{4-[(S)-(1-propyl-1H-imidazol-5-yl)methanesulfinyl]phenyl}carboxamide and 4-(2-butoxyethoxy)phenyl groups at positions 1, 5 and 8, respectively. It is a potent chemokine 2 and 5 receptor antagonist currently in development for the treatment of liver fibrosis in adults with nonalcoholic steatohepatitis (NASH). cenicriviroc: an inhibitor of HIV-1 | aromatic ether; benzazocine; diether; imidazoles; secondary carboxamide; sulfoxide | anti-HIV agent; anti-inflammatory agent; antirheumatic drug; chemokine receptor 2 antagonist; chemokine receptor 5 antagonist |