T Lymphocytes (Cns) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
T-lymphocytes (T cells) are key players in the adaptive immune system and have complex relationships with the central nervous system. While the CNS was once considered immune-privileged, it's now clear that T cells actively traffic through CNS compartments, participate in immune surveillance, and contribute to both protective immunity and pathogenic inflammation in neurodegeneration.
T cells in the CNS include several populations:
- CNS-resident T cells: Low numbers in healthy brain
- Meningeal T cells: More abundant in meninges
- CSF T cells: Naive and memory populations
- Infiltrating T cells: Increased during neuroinflammation
Key characteristics:
- T-cell receptor (TCR) for antigen recognition
- CD4+ (helper) and CD8+ (cytotoxic) subsets
- Require antigen presentation by MHC
- Can be protective or pathogenic
- Th1: IFN-γ producers, cellular immunity
- Th2: IL-4, IL-5, IL-13, humoral immunity
- Th17: IL-17, IL-22, autoimmunity
- Treg: IL-10, TGF-β, immune regulation
- Tfh: B-cell help in germinal centers
- Kill infected or abnormal cells
- MHC-I restricted
- Important in viral encephalitis
- Can target neurons in some conditions
- CD3: T-cell co-receptor
- CD4: Helper T-cell marker
- CD8: Cytotoxic T-cell marker
- CD45RO: Memory T-cell marker
- CCR7: Naive/central memory vs. effector memory
- FoxP3: Regulatory T-cell transcription factor
- RORγt: Th17 transcription factor
- Patrol CNS for pathogens
- Monitor for transformed cells
- Respond to damage signals
- Maintain CNS immune homeostasis
- Clear infections (viral, bacterial)
- Respond to tumor antigens
- Coordinate with microglia
- Support BBB repair
- CD8+ T cells accumulate in AD brain
- Th1/Th17 polarization in periphery
- Tregs may lose regulatory function
- T cells can recognize Aβ
- T-cell infiltration in substantia nigra
- CD4+ Th1/Th17 responses
- Tregs often reduced or dysfunctional
- α-Synuclein-specific T cells
- CD4+ Th1/Th17 driven autoimmunity
- CD8+ T cells in lesions
- Tregs deficient in function
- Molecular mimicry theories
- T-cell infiltration in spinal cord
- Regulatory vs. pathogenic balance
- Modulates microglial activation
- T-cell modulation: Altering T-cell responses
- Treg enhancement: Regulatory T-cell therapies
- Checkpoint inhibitors: Modulating T-cell activation
- CAR-T cells: Engineered T-cell therapies
The study of T Lymphocytes (Cns) has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Fletcher JM, et al. (2010). T cells in multiple sclerosis. Br Med Bull. PMID:20460231
- Brochard V, et al. (2009). Infiltration of CD4+ lymphocytes into the brain accelerates Parkinson disease. J Clin Invest. PMID:19669199
- Gate D, et al. (2020). CD4+ T cells contribute to neurodegeneration in Alzheimer's disease. Nature. PMID:32757460
- Reynolds AD, et al. (2010). Regulatory T cells attenuate Th17 cell-mediated nigrostriatal dopaminergic neurodegeneration. J Immunol. PMID:20483727
- Beers DR, et al. (2020). T cells as a therapeutic target in ALS. Mol Neurodegener. PMID:33076952