CXCL8 (IL-8): Complete Research Profile — CXCR1/CXCR2 Receptor Axes, Neutrophil Chemotaxis, Tumor Microenvironment Biology, and Inflammatory Research Applications (2026)

# CXCL8 (IL-8): Complete Research Profile — CXCR1/CXCR2 Receptor Axes, Neutrophil Chemotaxis, Tumor Microenvironment Biology, and Inflammatory Research Applications (2026)

For Research Use Only (RUO) — Not for human or veterinary use

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Introduction: CXCL8 as the Archetypical Neutrophil Chemoattractant

CXCL8, originally designated Interleukin-8 (IL-8), occupies a foundational position in chemokine biology. Discovered in 1987 and cloned in 1988, it was among the first chemokines characterized as a potent, selective recruiter of neutrophils to sites of inflammation. The rename to CXCL8 under the systematic chemokine nomenclature reflects its membership in the CXC subfamily — defined by two N-terminal cysteines separated by a single non-conserved residue — and its eighth position within that subgroup.

CXCL8 is produced by an extraordinarily broad array of cell types: monocytes, macrophages, neutrophils themselves (autocrine amplification), endothelial cells, epithelial cells, fibroblasts, and various tumor cell lines. Stimuli capable of triggering CXCL8 transcription include bacterial lipopolysaccharide (LPS), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), hypoxia, reactive oxygen species (ROS), and shear stress on endothelium. This breadth of inducers underscores CXCL8's role as an early-response integrator in the innate immune cascade.

From a research standpoint, CXCL8 is valuable precisely because it connects structural biology (its dimerization-dependent receptor engagement), cell biology (neutrophil polarity and migration mechanics), and disease biology (from acute lung injury to colorectal carcinogenesis). This profile provides a mechanistic foundation for investigators designing in vitro chemotaxis assays, murine model equivalents, tumor microenvironment studies, and receptor pharmacology experiments.

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Molecular Architecture and Isoforms

Primary Structure and Processing

The human CXCL8 gene encodes a 99-amino-acid precursor containing a 22-residue signal peptide. Proteolytic removal yields the dominant secreted form: CXCL8(1–77). However, extracellular processing by serine proteases — particularly cathepsin G, proteinase 3, and thrombin — can generate truncated N-terminal variants, most notably CXCL8(6–77) and CXCL8(8–77).

These truncated forms are not simply shorter versions of the same molecule. N-terminal truncation substantially alters receptor selectivity and potency:

• •CXCL8(1–77): Binds both CXCR1 and CXCR2 with high affinity
• •CXCL8(6–77): Retains dual receptor binding but with slightly altered CXCR1 affinity
• •CXCL8(8–77): Generated in inflamed joints; has altered receptor engagement kinetics

This protease-dependent isoform generation means that the functional CXCL8 landscape at an inflammatory site is not monolithic — it reflects the local protease environment. Researchers using recombinant CXCL8 should specify which isoform was used, as activity differences can be significant across assay contexts.

Three-Dimensional Structure

CXCL8 exists in solution as a monomer–dimer equilibrium. The monomeric form predominates at nanomolar concentrations typical of receptor activation assays, while the dimeric form is favored at higher concentrations and upon heparan sulfate proteoglycan (HSPG) binding.

The monomer folds into the canonical chemokine topology: a disordered N-terminus followed by a 310-helix, a three-stranded β-sheet (β1–β3), and a C-terminal α-helix. Two disulfide bonds — Cys7–Cys34 and Cys9–Cys50 — stabilize the core fold. The N-loop and β3-strand contribute to receptor binding, while the N-terminus (residues 1–8) constitutes the receptor activation domain.

Dimer formation occurs through a parallel interface involving the first β-strand. The dimer interface residues (Leu25, Val27, Leu66) are well characterized from NMR and X-ray crystallographic studies. Importantly, research by Clark-Lewis et al. (1991) demonstrated that monomeric CXCL8 mutants locked in the monomeric state retained full CXCR1/CXCR2 activation capacity, clarifying that dimerization itself is not required for receptor signaling but may facilitate HSPG-dependent presentation at vessel walls.

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Receptor Biology: CXCR1 and CXCR2

CXCR1 — High-Selectivity Signaling Receptor

CXCR1 (also designated IL-8RA) is a 350-amino-acid seven-transmembrane GPCR. Among human CXC chemokines, CXCL8 is the predominant CXCR1 ligand; CXCL6 can also bind with lower affinity. This relative selectivity makes CXCR1 the receptor of choice when investigators wish to study CXCL8-specific biology without contributions from other ELR+ CXC chemokines.

CXCR1 couples primarily to Gαi proteins, leading to:

• •Adenylyl cyclase inhibition → reduced cAMP
• •Phospholipase C-β (PLCβ) activation → IP3/DAG second messengers
• •Intracellular Ca²⁺ mobilization
• •PI3K-γ activation → Akt/PKB signaling
• •ERK1/2 MAP kinase cascade activation

A defining feature of CXCR1 signaling is its activation of the NADPH oxidase complex in neutrophils (respiratory burst). This is mediated through Gβγ subunit release, which activates p47phox phosphorylation and p21-Rac GTPase, leading to superoxide generation. This property makes CXCR1 particularly important for neutrophil antimicrobial capacity research.

CXCR2 — Promiscuous Amplification Receptor

CXCR2 (IL-8RB) binds all ELR-positive CXC chemokines: CXCL8, CXCL1 (GRO-α), CXCL2 (GRO-β), CXCL3 (GRO-γ), CXCL5 (ENA-78), CXCL6, and CXCL7 (NAP-2). This promiscuity positions CXCR2 as the primary integrator of neutrophil-recruiting signals across the ELR+ chemokine landscape.

Structurally, CXCR1 and CXCR2 share 77% amino acid identity in the transmembrane domains but differ significantly in their second extracellular loop (ECL2) and intracellular C-terminal tail. These differences confer distinct desensitization kinetics:

• •CXCR1: Undergoes relatively slow internalization (minutes); resistant to homologous desensitization at low ligand concentrations
• •CXCR2: Rapidly internalized via GRK2/6-mediated phosphorylation and β-arrestin recruitment; significant internalization within 5–10 minutes of ligand exposure

The differential desensitization has important research implications. In sustained inflammatory environments, CXCR1 surface expression is maintained longer than CXCR2, potentially making CXCR1 the dominant functional receptor during prolonged neutrophil activation states.

The Two-Site Receptor Activation Model

Chemokine receptor activation follows a two-site binding mechanism, thoroughly documented for CXCL8:

1. Site 1 (docking): The CXCL8 core domain (N-loop, β3-strand) engages the receptor N-terminus and ECLs. This interaction is high-affinity (~Kd 1–5 nM for CXCL8:CXCR1) but produces no receptor activation alone.

2. Site 2 (trigger): The CXCL8 N-terminal residues (particularly Glu4, Leu5, Arg6 — the ELR motif plus flanking residues) insert into the transmembrane bundle and activate the receptor through conformational change.

The ELR (Glu-Leu-Arg) motif immediately preceding the first cysteine is a defining structural feature of neutrophil-recruiting CXC chemokines. Mutation of the ELR motif abolishes receptor activation without disrupting receptor binding, creating useful CXCL8-based antagonist tools. CXCL8(ELR→ALA) constructs have been used in research to competitive-inhibit endogenous CXCL8 without activating CXCR1/2 signaling.

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Downstream Signaling Cascades

Calcium Flux and Neutrophil Activation

CXCL8-CXCR1/2 engagement triggers rapid intracellular calcium mobilization that serves as a central signaling hub:

• •Gαi releases the Gβγ dimer, which directly activates PLCβ2/β3
• •IP3 binding to endoplasmic reticulum IP3 receptors releases stored Ca²⁺
• •Secondary Ca²⁺ influx through store-operated channels (SOC/CRAC channels) sustains the signal

Peak [Ca²⁺]i typically reaches 300–600 nM within 10–20 seconds of CXCL8 addition in Fluo-4 AM or Fura-2 AM calcium imaging assays. This calcium transient coordinates the cytoskeletal reorganization required for chemotaxis via calmodulin-kinase and Rac/Cdc42 GTPase pathways.

PI3K-γ/Akt/mTOR Axis

The PI3K-γ isoform is uniquely activated by Gβγ subunits downstream of Gi-coupled GPCRs. In neutrophils, CXCL8:

• •Activates PI3K-γ, generating PIP3 at the leading edge
• •PIP3 recruits Akt (PKB) via PH domain interaction
• •Akt activates mTORC1, which coordinates protein synthesis during the extended inflammatory response
• •PIP3 also activates the exchange factor DOCK2, enabling Rac2 activation and F-actin polymerization at the pseudopod

Research using PI3K-γ inhibitors (e.g., PI-3065, IPI-145 [duvelisib]) in neutrophil chemotaxis assays toward CXCL8 gradients have quantified PI3K-γ's contribution as responsible for approximately 70–80% of directed migration in under-agarose or transwell chemotaxis systems.

MAPK Cascade

ERK1/2 (p44/p42 MAPK) activation downstream of CXCL8/CXCR2 occurs through both Gi-dependent and Gi-independent pathways. The Gi-independent route involves β-arrestin-mediated ERK scaffold formation — a mechanism that persists even after G protein desensitization, providing biased signaling options. Phospho-ERK activation peaks at 5–15 minutes post-CXCL8 stimulation in monocyte and neutrophil models.

p38 MAPK is co-activated in CXCL8-stimulated neutrophils and contributes to degranulation of secondary (specific) granules containing lactoferrin, collagenase, and gelatinase. p38 inhibition with SB203580 significantly reduces CXCL8-driven degranulation in vitro, making it a useful negative control in granule release studies.

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Neutrophil Biology and Chemotaxis Mechanisms

The Chemotaxis Machinery

CXCL8 is among the best-studied neutrophil chemoattractants for investigating the molecular machinery of directed cell migration. Key research insights include:

Front-rear polarity establishment: Upon CXCL8 gradient exposure, neutrophils rapidly establish a front characterized by PIP3 accumulation, Rac2 activation, and lamellipodia extension. The rear of the cell accumulates myosin IIa (phosphorylated via ROCK kinase), PTEN (which degrades PIP3), and Rho-dependent contractility that drives rear retraction.

Compass vs. motor functions: Using micropipette assays and microfluidic gradient chambers, investigators have distinguished CXCL8's "compass" role (gradient sensing via PIP3 polarity) from its "motor" role (overall migration speed via PI3K-independent pathways). This distinction matters for assay design: gradient-sensing experiments require defined, stable gradients (microfluidic devices or under-agarose systems) rather than transwell setups which measure total migration but obscure directionality.

Hierarchical chemokine signaling: In complex mixtures of chemotactic signals, CXCL8/CXCR1 signals are classified as "end-target" signals (tissue chemoattractants) that dominate over "intermediary" signals (e.g., C5a, fMLP) in neutrophil navigation decisions. This hierarchy is well characterized by Foxman et al. using fluorescence-based tracking assays.

Heparan Sulfate Proteoglycan Interactions

Like most chemokines, CXCL8 displays high affinity for heparan sulfate (HS) chains on cell surfaces and extracellular matrix. The HS-binding site on CXCL8 maps primarily to the C-terminal α-helix (residues 55–72), particularly the KELRCQC sequence and residues K64, K67, K72.

HS binding serves multiple research-relevant functions:

1. Gradient formation: HS immobilizes CXCL8 at tissue sites, creating stable haptotactic gradients rather than diffusion-governed gradients

2. Protection from degradation: HS-bound CXCL8 is substantially more resistant to proteolytic inactivation

3. Receptor presentation: Some evidence suggests HS-bound CXCL8 can be "trans-presented" to CXCR1/2 on rolling neutrophils, facilitating arrest

Heparin competition assays and HS-binding mutant CXCL8 (e.g., K64A/K67A/K72A) are standard tools for delineating HS-dependent vs. HS-independent CXCL8 activities in vitro. Researchers must account for the HS content of serum-containing media, which can compete with CXCL8 binding in cell-based assays.

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Transcriptional Regulation of CXCL8 Expression

NF-κB as the Central Driver

The CXCL8 promoter (−546 to +44 bp) contains overlapping binding sites for multiple transcription factors, but NF-κB (particularly the p50/p65 heterodimer) is the dominant driver of LPS- and cytokine-induced CXCL8 transcription. The NF-κB binding element at −80 bp is essential; deletion or mutation of this site ablates >90% of IL-1β- or TNF-α-induced promoter activity in reporter assays.

NF-κB activation proceeds via:

• •IKK complex (IKKβ-dominant) phosphorylation of IκBα at Ser32/Ser36
• •IκBα ubiquitination (K48-linked) and proteasomal degradation
• •Nuclear translocation of p65, binding to the CXCL8 promoter
• •Recruitment of coactivators CBP/p300 and BRD4

This pathway is experimentally blocked by IKK inhibitors (e.g., BMS-345541, TPCA-1), proteasome inhibitors (MG-132), or dominant-negative IκBα (S32A/S36A mutant) in transient transfection studies.

AP-1 and C/EBP Co-regulation

The AP-1 site at −126 bp (binding c-Jun/c-Fos heterodimers) synergizes with NF-κB for maximal CXCL8 induction. C/EBP-β (NF-IL-6) also binds at −96 bp. The convergence of NF-κB, AP-1, and C/EBP creates a combinatorial transcriptional logic that varies by stimulus:

• •LPS + IFN-γ: strong NF-κB + IRF-3 component
• •IL-17A: C/EBP-dependent pathway, partially NF-κB-independent
• •Hypoxia: HIF-1α binding to hypoxia-response element (HRE) at −200 bp; independent of classical NF-κB

Understanding which transcriptional program drives CXCL8 in a given experimental context helps investigators select appropriate pathway-blocking controls and reporter constructs.

mRNA Stability — The ARE Axis

CXCL8 mRNA contains multiple AU-rich elements (AREs) in its 3' UTR. These AREs recruit RNA-binding proteins that regulate mRNA half-life:

• •TTP (ZFP36/TIS11): Destabilizing; promotes ARE-mediated mRNA decay
• •HuR (ELAVL1): Stabilizing; competes with TTP for ARE binding
• •AUF1: Context-dependent; can stabilize or destabilize

p38 MAPK phosphorylates MK2, which phosphorylates TTP, preventing its mRNA-destabilizing function. This explains why p38 inhibition with SB203580 reduces CXCL8 protein output without fully suppressing promoter activity — a dual transcriptional/post-transcriptional mechanism.

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Tumor Microenvironment: CXCL8 in Cancer Biology

Autocrine and Paracrine Tumor CXCL8

Many solid tumor types express CXCL8 constitutively, with elevated levels correlating with poor prognosis in colorectal, lung, bladder, cervical, and prostate carcinoma studies. CXCL8 in the tumor microenvironment (TME) serves multiple pro-tumorigenic functions:

Autocrine proliferation: Tumor cells expressing CXCR1 and/or CXCR2 respond to self-secreted CXCL8 through ERK1/2 and PI3K/Akt activation, driving cell cycle progression. This was characterized in colorectal cancer lines (HCT116, SW480) by Brew et al., where CXCL8-CXCR2 autocrine loops accelerated S-phase entry.

Angiogenesis promotion: CXCL8 is a potent angiogenic factor. It stimulates endothelial cell migration and tube formation via CXCR2 and, to a lesser extent, by directly potentiating VEGF receptor signaling. The Elisseeff group demonstrated that CXCL8 synergizes with VEGF-A in Matrigel tube formation assays, with combined activity exceeding the additive sum of individual cytokines.

Myeloid cell recruitment: TME-derived CXCL8 recruits CXCR1/2-expressing neutrophils and myeloid-derived suppressor cells (MDSCs). Tumor-associated neutrophils (TANs) and MDSCs recruited by CXCL8 promote immune evasion through TGF-β secretion, arginase-1 expression, and ROS-mediated T cell suppression.

Epithelial-mesenchymal transition (EMT): CXCL8 promotes EMT in multiple cancer cell lines by upregulating Snail, Slug, and Vimentin while downregulating E-cadherin. This effect proceeds through CXCR1-PI3K-Akt-NF-κB and CXCR2-ERK1/2-Slug cascades.

CXCL8 and Therapy Resistance

Research publications have documented CXCL8 upregulation in response to multiple cancer therapies as a resistance mechanism:

• •Chemotherapy: Platinum agents (cisplatin, oxaliplatin) induce DNA damage-response-linked NF-κB activation, elevating CXCL8 and creating a paracrine survival loop
• •VEGF-targeted therapy: Anti-VEGF treatment (bevacizumab) paradoxically elevates CXCL8, potentially through tumor hypoxia-HIF1α-mediated transcription
• •EGFR inhibitors: KRAS-mutant colorectal cancer cells upregulate CXCL8 upon cetuximab treatment via STAT3 compensatory activation

These findings have spurred research interest in CXCL8/CXCR2 inhibition as a combination strategy. SB225002 (CXCR2-selective antagonist) and reparixin (CXCR1/2 allosteric inhibitor) are frequently employed in in vitro combination studies examining CXCL8-mediated therapy resistance mechanisms.

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In Vitro Research Models and Assay Design

Recombinant CXCL8 Characterization

When selecting recombinant CXCL8 for research, key specifications include:

• •Source: E. coli-derived (most common; cost-effective) vs. mammalian/insect cell-derived (for glycosylation-competent contexts, though native CXCL8 is not glycosylated)
• •Isoform: CXCL8(1–77) or CXCL8(8–77); confirm by N-terminal sequencing or intact mass
• •Purity: ≥95% by SDS-PAGE and RP-HPLC
• •Endotoxin: <1 EU/µg (critical for inflammatory assays to avoid LPS contamination artifacts)
• •Activity validation: EC50 in neutrophil chemotaxis or calcium flux assay

Typical EC50 values for reference:

• •CXCR1 calcium flux (HL60-differentiated cells): 1–5 nM
• •CXCR2 calcium flux: 5–30 nM
• •Neutrophil transwell migration: 5–50 nM (optimum typically ~10 nM for maximal directionality)

Chemotaxis Assay Systems

Transwell (Boyden chamber) assays: Most widely used; simple, quantitative. CXCL8 in lower chamber, neutrophils or CXCR-expressing cells in upper chamber. Polycarbonate membranes (3–8 µm pore size for neutrophils). Caveat: measures total transmigration, not directionality; bidirectional gradient not maintained.

Under-agarose assays: Cells migrate under 0.5% agarose from a loading well toward CXCL8-containing wells. Permits direct visualization of migration tracks and genuine chemotaxis scoring. Well-suited for neutrophil speed and directionality measurements.

Microfluidic gradient chambers: Gold standard for chemotaxis research; produce stable, defined concentration gradients. The EZ-TAXIScan and Ibidi µ-Slide chemotaxis systems allow real-time imaging. These systems have been used to study CXCL8 gradient threshold sensing (minimum detectable gradient: ~1% concentration difference across cell body).

3D migration assays: Collagen gel or fibrin matrix embedded assays for studying CXCL8-driven invasion relevant to cancer cell biology. Different matrix stiffness (0.5–4 mg/mL collagen) modulates CXCL8-driven migration speed significantly.

Calcium Flux Protocols

Standard protocol for CXCL8-driven Ca²⁺ mobilization:

1. Load cells (neutrophils, HL60, CXCR1/2-transfected HEK293) with 5 µM Fluo-4 AM (37°C, 45 min)

2. Wash and resuspend in HEPES-buffered saline (no Ca²⁺ for CXCR1-specific ER release; +1 mM CaCl₂ for full response)

3. Baseline acquisition for 30 seconds, then add CXCL8 (0.1–100 nM concentration-response)

4. Measure peak ΔF/F₀ ratio at 15–30 second post-addition

CXCR1-expressing HEK293 cells are a clean model for signaling pathway delineation free from neutrophil-specific secondary effects. CXCR2-expressing cells require similar setup but will respond to all ELR+ CXC chemokines — include appropriate chemokine pretreatment controls for desensitization studies.

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Murine Research Considerations

The CXCL8 Orthologue Problem

Mice do not possess a true CXCL8 orthologue. The functional equivalents in murine neutrophil biology are:

• •CXCL1 (KC/GRO-α): Primary CXCR2 ligand in mice; closest functional equivalent
• •CXCL2 (MIP-2): Second major murine neutrophil chemoattractant
• •CXCL5 (LIX): Epithelial-derived; relevant for pulmonary models

CXCR1 in mice binds LIX/CXCL5 but does not respond to human CXCL8. Murine CXCR2 can weakly bind human CXCL8, but murine CXCL1 is ~50-fold more potent for murine CXCR2.

This cross-species discordance has important implications:

• •Humanized mouse models expressing human CXCR1/CXCR2 are required for human CXCL8 response studies in vivo
• •Caution when extrapolating human in vitro CXCL8 data to murine in vivo readouts — CXCL1/CXCL2 may be the appropriate surrogates
• •Transgenic CXCL8 mouse models (e.g., overexpressing human CXCL8 in skin) have been developed to study chronic neutrophilic skin inflammation

Published literature on murine peritonitis or lung inflammation induced by recombinant human CXCL8 should be interpreted cautiously unless CXCR humanization is documented.

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CXCL8 in Specific Research Contexts

Acute Lung Injury and ARDS Models

CXCL8 is among the most elevated cytokines in bronchoalveolar lavage fluid (BALF) of ARDS patients (~80-fold above controls). In vitro models of lung epithelial injury (A549 cells, human primary alveolar cells) show robust CXCL8 secretion in response to:

• •Stretch injury (cyclic mechanical strain simulating ventilator-induced lung injury)
• •LPS exposure (modeling gram-negative pneumonia)
• •Hyperoxia

CXCL8:CXCR2 research in pulmonary contexts frequently employs air-liquid interface (ALI) bronchial epithelial cultures (NHBE, 16HBE) and transepithelial neutrophil migration assays where a CXCL8 gradient is established across the epithelial layer.

Inflammatory Bowel Disease Models

In IBD research, CXCL8 expression in colonic epithelium and lamina propria macrophages is markedly elevated. In vitro IBD models relevant to CXCL8 research include:

• •Caco-2 polarized monolayers: Basolateral CXCL8 secretion is measured by ELISA after apical LPS, TNF-α, or IL-17A stimulation. Transepithelial electrical resistance (TEER) readings quantify barrier integrity alongside CXCL8 output.
• •Organoid-based models: Colonic organoids from mucosal biopsies maintain cell-type composition and polarization, offering more physiological CXCL8 regulation than immortalized lines.

Psoriasis and Skin Inflammation

Keratinocytes are abundant CXCL8 producers when stimulated by IL-17A, IL-22, and IL-1β — the signature cytokines of psoriatic inflammation. Normal human epidermal keratinocyte (NHEK) models with IL-17A stimulation (10–50 ng/mL) produce substantial CXCL8 (typically 50–500 pg/mL/24h depending on passage and confluence).

3D skin equivalent models incorporating keratinocytes on collagen dermal constructs provide a more complete context for studying CXCL8-driven neutrophil infiltration dynamics relevant to psoriatic plaque formation research.

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CXCL8 Protein Detection Methods

ELISA Considerations

Multiple high-sensitivity ELISA platforms detect CXCL8 in cell supernatants, serum/plasma, and BALF:

• •Standard sandwich ELISA: Detection range 2–3,000 pg/mL; suitable for high-expression contexts
• •Electrochemiluminescence (ECL, Meso Scale Discovery): Lower LOD (~0.5 pg/mL); useful for plasma samples where CXCL8 levels are low or studying baseline expression
• •Multiplex platforms (Luminex, LEGENDplex): Allow simultaneous CXCL8 quantification with other chemokines/cytokines

Cross-reactivity is rarely problematic for CXCL8-specific antibody pairs given its low homology with other CXC chemokines in epitope regions, but verify with panel validation if multiplexing with CXCL1/CXCL5 in murine samples.

Flow Cytometry and Intracellular Staining

CXCL8 is challenging to detect by intracellular staining (ICS) in neutrophils due to rapid secretion kinetics. Optimal ICS requires:

• •Brefeldin A or monensin treatment within minutes of stimulation
• •Short stimulation windows (2–4 hours maximum)
• •Fixation with paraformaldehyde-based fixatives compatible with CXCL8 epitope preservation

Surface detection of CXCL8 is less common but has been described on activated platelets and some tumor cells.

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CXCR1/CXCR2 Pharmacological Tools in Research

Reference Agonists and Antagonists

For CXCR2-specific research, SB225002 at 10–100 nM effectively blocks CXCL1, CXCL2, and CXCL8 responses while leaving CXCR1-mediated signals (respiratory burst) intact — useful for parsing receptor contributions in primary neutrophil studies.

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Relevant Citations

2. Clore GM, Appella E, Yamada M, Matsushima K, Gronenborn AM. Three-dimensional structure of interleukin 8 in solution. Biochemistry. 1990;29(7):1689–1696. PMID: 2322558. https://pubmed.ncbi.nlm.nih.gov/2322558/

3. Murphy PM, Tiffany HL. Cloning of complementary DNA encoding a functional human interleukin-8 receptor. Science. 1991;253(5025):1280–1283. PMID: 1891716. https://pubmed.ncbi.nlm.nih.gov/1891716/

5. Waugh DJ, Wilson C. The interleukin-8 pathway in cancer. Clin Cancer Res. 2008;14(21):6735–6741. PMID: 18980976. https://pubmed.ncbi.nlm.nih.gov/18980976/

6. Ha H, Debnath B, Neamati N. Role of the CXCL8-CXCR1/2 axis in cancer and inflammatory diseases. Theranostics. 2017;7(6):1543–1588. PMID: 28529637. https://pubmed.ncbi.nlm.nih.gov/28529637/

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All information is provided for research purposes only. CXCL8 and related materials are research reagents for in vitro laboratory investigation. Not for use in humans or animals. Investigators should consult institutional biosafety guidelines when working with recombinant cytokines.