IL15 (Interleukin-15) encodes a cytokine that is structurally related to IL-2 and shares many biological functions, but has distinct expression patterns and signaling mechanisms. IL-15 is critical for the development, survival, and function of natural killer (NK) cells, NK T cells, and certain T cell subsets. In the central nervous system, IL-15 is expressed in neurons, astrocytes, microglia, and oligodendrocytes, where it plays important roles in neuroinflammation, synaptic plasticity, and neuroprotection[1][2].
| Symbol | IL15 |
| NCBI Gene ID | 3600 |
| Chromosome | 4q31 |
| Protein Class | Cytokine receptor |
| Molecular Weight | ~17 kDa (ligand) |
IL-15 is a cytokine with diverse functions in both immune and nervous systems:
IL-15 signals through a heterotrimeric receptor complex:
The IL-15/IL-15Rα complex can also present in trans to neighboring cells expressing IL-2Rβ/γc[6].
IL-15 activates multiple signaling cascades:
IL-15 is widely expressed in:
| Cell Type | Expression Level | Notes |
|---|---|---|
| Neurons | Moderate | Higher in cortex and hippocampus |
| Astrocytes | High | Inducible under inflammatory conditions |
| Microglia | High | Constitutive expression, upregulated in disease |
| Oligodendrocytes | Low | Some expression in white matter |
| Peripheral immune cells | High | NK cells, monocytes, dendritic cells |
IL-15 pathway is being explored for therapeutic intervention:
Polliz et al. IL-15 in the CNS (2002). 2002. ↩︎
Gomez-Nicola et al. IL-15 and neuroinflammation (2014). 2014. ↩︎
Kennedy et al. IL-15 and NK cells (2000). 2000. ↩︎
Schluns et al. IL-15 and memory CD8+ T cells (2000). 2000. ↩︎
Panga et al. IL-15 neuroprotection in PD (2019). 2019. ↩︎
Dubois et al. [IL-15 trans-presentation (2002)](https://doi.org/10.1016/S1074-7613(02). 2002. ↩︎
Zhao et al. IL-15 in Alzheimer's disease (2013). 2013. ↩︎
Ljunggren et al. IL-15 and Parkinson's disease (2015). 2015. ↩︎
Fischer et al. IL-15 in ALS (2017). 2017. ↩︎