Adaptive immune lymphocytes that develop in the thymus and mediate cell-mediated immunity through cytotoxic killing (CD8+ T cells) or immune orchestration via cytokine production (CD4+ helper T cells). T cells express T cell receptors (TCRs) that recognize specific antigens presented on MHC molecules.
Naive T cells are activated when their TCR binds to antigen-MHC complexes on antigen-presenting cells (dendritic cells, macrophages) along with co-stimulatory signals (CD28-B7). CD4+ T cells differentiate into Th1 (IFN-Ξ³, cell-mediated immunity), Th2 (IL-4, antibody responses), Th17 (IL-17, mucosal immunity), or Treg (IL-10, immunosuppression) subsets. CD8+ cytotoxic T cells release perforin and granzymes to kill infected/malignant cells. T cells express dopamine receptors, beta-adrenergic receptors, and glucocorticoid receptors allowing direct neuroendocrine regulation.
T cell dysfunction underlies autoimmune diseases (Th1/Th17 dominance), allergies (Th2 dominance), cancer (exhaustion/Treg suppression), and chronic infections. In cPNI, chronic stress causes T cell redistribution, suppression via cortisol, and Th1/Th2 imbalances. Interventions focus on restoring T cell balance through stress reduction, microbiome optimization, and addressing chronic inflammation.
- CD4+ helper T cells coordinate immune responses via cytokine production
- CD8+ cytotoxic T cells kill infected and malignant cells
- Th1 cells produce IFN-Ξ³ and IL-2, driving cell-mediated immunity
- Th2 cells produce IL-4, IL-5, IL-13, promoting antibody responses and allergies
- Th17 cells produce IL-17 and IL-22, important for mucosal barrier defense
- Regulatory T cells (Tregs) suppress immune responses via IL-10 and TGF-Ξ²
- T cells express dopamine receptors (D1-D5) allowing neurotransmitter modulation
- Chronic stress causes T cell redistribution from lymph nodes to tissues
- T cell exhaustion in cancer/chronic infection involves PD-1 and CTLA-4 upregulation
- macrophages β Antigen-presenting cells activating T cells and responding to T cell cytokines
- dendritic cells β Professional antigen-presenting cells priming naive T cells
- B cells β Receive T cell help (CD40L-CD40) for antibody class switching
- NK cells β Innate lymphocytes bridging innate and adaptive immunity with T cells
- cytokines β Primary effector molecules produced by T helper cells
- IFN-Ξ³ β Signature Th1 cytokine activating macrophages and cell-mediated immunity
- IL-4 β Signature Th2 cytokine promoting B cell antibody production and allergies
- IL-10 β Immunosuppressive cytokine produced by Tregs
- cortisol β Suppresses T cell proliferation and shifts Th1/Th2 balance toward Th2
- dopamine β Modulates T cell proliferation and cytokine production via dopamine receptors
- dopamine receptors β Expressed on T cells allowing direct neurotransmitter regulation
- chronic stress β Causes T cell redistribution, immunosuppression, and Th1/Th2 imbalance
- gut microbiome β Shapes T cell development, Treg induction, and Th17 differentiation
- SCFAs β Microbial metabolites promoting Treg differentiation
- autoimmune disease β Often involves autoreactive T cells escaping tolerance mechanisms
- cancer β T cell exhaustion and Treg suppression enable tumor immune evasion
- inflammation β T cells orchestrate inflammatory responses via cytokine networks
- BDNF β T cells express BDNF receptors; stress affects T cell function via neurotrophin pathways
- HPA axis β Chronic HPA activation suppresses T cell function via cortisol
- sympathetic nervous system β Catecholamines modulate T cell trafficking and cytokine production
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