Table 1 The major population of immune cells involved in neuroimmune interactions
From: Beyond the gut: decoding the gut–immune–brain axis in health and disease
Cell type | Location/Distribution | Specific markers/subtypes | Key functions | Ref |
|---|---|---|---|---|
Microglia | CNS parenchyma | CD11b, F4/80, CX3CR1, IBA1, TREM119, P2RY12, Siglec-H | • Originate from the yolk sac during early development • Play key roles in immune surveillance and sensing danger signals • Engage in phagocytosis of neural progenitor cells and synaptic elements • Provide neurotrophic support through factors such as IGF-1 and BDNF • Respond to cytokines (e.g., IL-4, IFN-γ), enabling dynamic shifts in functional states | [67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89, 380] |
Astrocytes | Throughout the CNS | GFAP, S100β, ALDH1L1 | • Phagocytose apoptotic neurons and clear myelin debris • Provide structural support and regulate neurotransmitters to maintain extracellular homeostasis • Contribute to phagocytosis and overall debris clearance • Secrete IL-33 to recruit microglia for synaptic remodeling • Interact with vascular endothelial cells to help maintain BBB integrity | |
Conventional T Cells | Dural/leptomeningeal regions, Choroid plexus, few in brain parenchyma | CD44, CD69, CD103 | • Accumulate in the central nervous system (CNS) after birth • Modulate neuronal function through cytokine signaling (e.g., IFN-γ, IL-4) • Support the maturation and functional development of microglia | |
Regulatory T Cells (Tregs) | Dural/leptomeningeal regions, choroid plexus, and few in brain parenchyma | CTLA-4, ICOS, ST2,5-HT7 | • Exhibit a tissue-resident phenotype, distinct from circulating Tregs • Contribute to inflammation resolution and tissue repair by producing IL-10, TGF-β, AREG, and SPP1, which suppress inflammation and promote recovery | |
Gamma Delta T Cells | Predominantly in the dural meninges | High IL-17A production | • Accumulate early in the meninges • Secrete high levels of IL-17A, modulating synaptic plasticity and influencing anxiety-like behaviors | |
B Cells | Dural/leptomeningeal regions, choroid plexus, and few in brain parenchyma | Adults: Immature & B2 cells; Neonatal: B-1a cells | • Mediate local negative selection within the meninges • Promote proliferation of oligodendrocyte precursor cells during neonatal development | |
Border-Associated Macrophages (BAMs) | CNS borders: meninges, choroid plexus, and perivascular spaces | Ms4a7, Ms4a6c, Tgfbi, Lyz2 | • Involved in antigen presentation and immune clearance • Regulate BBB permeability through NOX2. | |
Innate Lymphocytes (NK Cells & ILCs) | Dural/leptomeningeal regions, choroid plexus, and few in brain parenchyma | NK cells, ILC1s, ILC2s, few ILC3s | • Accumulate in the meninges after birth • ILC2 produce IL-13 to regulate inhibitory synapse development • ILC2 accumulation in the aged brain is associated with age-related cognitive function |
