IL16 (Interleukin-16) <table class="infobox infobox-gene">Symbol </td>NCBI Gene ID </td>Chromosome </td>Protein Class </td>Molecular Weight </td>
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IL16 (Interleukin-16) <table class="infobox infobox-gene">Symbol </td>NCBI Gene ID </td>Chromosome </td>Protein Class </td>Molecular Weight </td>
Overview
Mermaid diagram (expand to render)
IL16 (Interleukin-16) encodes a cytokine originally identified as a chemoattractant factor for CD4+ T cells, now recognized as a multifunctional cytokine with roles in immune regulation, neuroinflammation, and cell survival. IL-16 is unique among cytokines as it is synthesized as a propeptide that requires proteolytic processing to become active. In the nervous system, IL-16 is expressed in [neurons](/entities/neurons), [astrocytes](/entities/astrocytes), and [microglia](/cell-types/microglia-neuroinflammation), where it modulates inflammatory responses and may play roles in neurodegenerative diseases["@choi2004"][@smith2001].
Gene Overview
Function IL-16 has diverse biological functions:
Immune System
T cell chemoattraction : Originally characterized as "Lymphocyte chemoattractant factor (LCF)" - attracts CD4+ T cells, monocytes, and eosinophils[@center1996]CD4 expression : Induces CD4 expression on CD4- cellsImmunomodulation : Regulates T cell activation and cytokine productionNervous System
Neuroinflammation : Modulates microglial activation and pro-inflammatory cytokine productionNeuronal function : May affect neuronal excitability and synaptic transmission[Blood-brain barrier](/entities/blood-brain-barrier) : May influence BBB permeability during inflammationProcessing and Activation IL-16 is synthesized as a precursor (pro-IL-16) that undergoes proteolytic cleavage:
Pro-IL-16 : Full-length precursor (~631 amino acids)Caspase-3 cleavage : Generates mature, active IL-16Mature IL-16 : Active form (~121 amino acids), forms tetramersThe unique processing mechanism links IL-16 to [apoptosis](/entities/apoptosis) regulation since caspase-3 is activated during programmed cell death[@zhang1998].
Receptor IL-16 signals through CD4 (cluster of differentiation 4) as a co-receptor:
Primary receptor : CD4 (on T cells, monocytes, dendritic cells)Alternative binding : May interact with other proteins including MHC class IISignaling : CD4-associated Lck kinase initiates downstream signaling cascadesSignaling Pathways IL-16 activates multiple pathways:
MAPK/ERK pathway : Cell proliferation and differentiationPI3K/Akt pathway : Cell survival and growthJAK/STAT pathway : Gene transcription[NF-κB](/entities/nf-kb) pathway : Inflammatory gene expression
Disease Associations
Neurodegenerative Diseases
Alzheimer's Disease : IL-16 levels elevated in AD brain; correlates with disease severity; potential biomarker[@li2016]Parkinson's Disease : Increased IL-16 in CSF of PD patients; involved in dopaminergic neuron inflammation[@mogi2009]Multiple Sclerosis : Elevated in MS lesions and CSF; contributes to autoimmune inflammation[@baranzini2000]Huntington's Disease : Altered IL-16 expression in HD modelsOther Conditions
HIV/AIDS: Elevated in patients; correlates with disease progression
Asthma: Pro-inflammatory role in airway inflammation
Rheumatoid arthritis: Contributes to synovial inflammation
Expression IL-16 is widely expressed:
Therapeutic Potential IL-16 targeting strategies:
IL-16 antagonists : Potential for treating autoimmune diseasesBiomarker utility : IL-16 as a biomarker for neuroinflammationDrug development : IL-16 modulators in development for MS and RACross-References
[Alzheimer's Disease](/diseases/alzheimers-disease)
[Parkinson's Disease](/diseases/parkinsons-disease)
[Multiple Sclerosis](/diseases/multiple-sclerosis)
[Neuroinflammation](/mechanisms/neuroinflammation)
[Cytokine Signaling](/mechanisms/cytokine-signaling)
[Microglia](/cell-types/microglia)
See Also
[Alzheimer's Disease](/diseases/alzheimers-disease)
[Parkinson's Disease](/diseases/parkinsons-disease)
[Multiple Sclerosis](/diseases/multiple-sclerosis)
[Neuroinflammation](/mechanisms/neuroinflammation)
[Cytokine Signaling](/mechanisms/cytokine-signaling)
External Links
[NCBI Gene: 3603](https://www.ncbi.nlm.nih.gov/gene/3603)
References
[Choi et al., IL-16 in neuroinflammation (2004) (2004)](https://doi.org/10.1016/j.neulet.2004.05.080)
[Smith et al., IL-16 biology (2001) (2001)](https://doi.org/10.1016/S0092-8674(01)
[Center et al., IL-16 as lymphocyte chemoattractant (1996) (1996)](https://doi.org/10.1073/pnas.93.2.758)
[Zhang et al., Caspase-3 and IL-16 processing (1998) (1998)](https://doi.org/10.1073/pnas.95.6.3128)
[Li et al., IL-16 in Alzheimer's disease (2016) (2016)](https://doi.org/10.1186/s13195-016-0199-5)
[Mogi et al., IL-16 in Parkinson's disease CSF (2009) (2009)](https://doi.org/10.1007/s00401-008-0460-5)
[Baranzini et al., IL-16 in multiple sclerosis (2000) (2000)](https://doi.org/10.1093/brain/123.3.508)
Pathway Diagram The following diagram shows the key molecular relationships involving IL16 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)
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