Recombinant Human Interleukin-7 protein (IL7)
Description
Molecular Structure and Production
Structure
Recombinant human IL-7 is a disulfide-linked monomeric protein comprising 153 amino acids (26–177 aa) with a molecular weight of 17–17.5 kDa . It is structurally homologous to murine IL-7 (60% sequence identity) and belongs to the IL-7/IL-9 cytokine family .
Production Methods
| Supplier | Expression System | Purity | Biological Activity | Endotoxin Level |
|---|---|---|---|---|
| BioLegend | HEK 293 | ≥95% | N/A | ≤0.05 EU/µg |
| BPS Bioscience | E. coli | ≥97% | ≤0.5 ng/mL (ED₅₀) | <0.1 EU/µg |
| BD Biosciences | E. coli | >95% | >2 × 10⁶ units/mg | ≤0.1 ng/µg |
| Abcam | HEK 293 | ≥95% | Suitable for cell culture | ≤0.05 EU/µg |
Key notes: HEK 293-expressed IL-7 retains glycosylation, while E. coli-derived versions are non-glycosylated but retain functional activity .
Biological Functions
IL-7 exerts its effects via the IL-7 receptor (IL-7R), a heterodimer of IL-7Rα (CD127) and the common γ-chain (CD132) . Its primary roles include:
T-Cell Development and Homeostasis
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Thymic Development: Critical for T-cell progenitor survival and differentiation into mature T cells .
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Peripheral Homeostasis: Maintains naive and memory T-cell populations by upregulating anti-apoptotic proteins (e.g., Bcl-2, Mcl-1) .
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Immune Reconstitution: Enhances recovery of CD4⁺ and CD8⁺ T cells post-chemotherapy or hematopoietic stem cell transplantation (HSCT) .
B-Cell Regulation
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Early Development: Required for pro-B and pre-B cell proliferation in mice, but not in humans .
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Survival Signals: Modulates B-cell survival via Bcl-2 family proteins, though mature B cells lack IL-7Rα .
Other Immune Cells
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Dendritic Cells: Supports thymic dendritic cell accumulation and T-cell priming .
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Neutrophils/Eosinophils: Indirectly influences granulopoiesis via T-cell-derived cytokines (e.g., IL-17) .
Phase I Trials
Critical Observations:
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T-Cell Rejuvenation: RhIL-7 restores a "youthful" T-cell profile in elderly patients .
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B-Cell Effects: Polyclonal pre-B cell proliferation observed in some patients, though transient .
Mechanistic Insights
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Signaling Pathways: Activates JAK/STAT5 and PI3K/Akt/mTOR pathways, promoting cell survival and proliferation .
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Immune Reconstitution: Accelerates recovery of CMV-specific T cells post-allo-HSCT, reducing infection risk .
Therapeutic Applications
Future Directions
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Combination Therapies: Synergistic use with checkpoint inhibitors (e.g., PD-1/PD-L1 blockers) to enhance anti-tumor immunity.
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Biomarker-Driven Trials: Identifying IL-7Rα⁺ patient subsets for personalized dosing.
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Infectious Disease Focus: Evaluating efficacy in sepsis and viral immunosuppression (e.g., COVID-19, PML) .
Product Specs
Generally, the shelf life of the liquid form is 6 months at -20°C/-80°C. The shelf life of the lyophilized form is 12 months at -20°C/-80°C.
Target Background
- Human IL-7 exhibits stronger binding affinity to stretched Fibronectin compared to relaxed Fibronectin. PMID: 28845674
- Downregulation of IL-7 and T follicular helper cells (Tfh) might contribute to the persistence of hepatitis C virus (HCV) infection. In vitro studies have demonstrated the immunopotentiating effect of IL-7 in chronic HCV infection, leading to IL-7-regulated HCV-specific and nonspecific activated Tfh cells. PMID: 29672235
- Research suggests that IL-7 directly upregulates the growth and functional activity of human T cells in the absence of antigenic stimulation, while exhibiting relatively limited costimulatory effects. PMID: 30193429
- Findings further support the role of IL-7 as a key regulatory factor influencing the balance between different T-cell subsets following hematopoietic stem cell transplantation. PMID: 29033080
- The constitutively signaling C7R system, developed in recent research, delivers potent IL7 stimulation to CAR T cells, enhancing their persistence and antitumor activity against various preclinical tumor models, supporting its potential for clinical development. PMID: 28830878
- Studies have demonstrated that Imatinib mesylate (IM) impairs T cell survival by inhibiting IL-7 and STAT5-p signaling, while TCR signaling remains unaffected during IM therapy. Therefore, the off-target inhibitory effects of IM on IL-7 and STAT5-p explain the occurrence of T cell lymphopenia in patients undergoing IM treatment. PMID: 28387753
- A comparative study examined the plasma concentrations of IL-15 and IL-7 in patients with Myelodysplastic Syndromes (MDS) and healthy controls. PMID: 27036031
- Data strongly implicate IL-7 in the thymus-independent long-term survival of functional naive-Tregs. PMID: 26910841
- Research highlights the critical role played by IL-7 and IL-15 in T cell homeostasis and explores their potential for improving immune reconstitution after allogeneic stem cell transplantation. PMID: 26795458
- The IL-7/IL-7R signaling pathway is implicated in recurrent pregnancy loss by upregulating Th17 immunity while downregulating Treg immunity. PMID: 27767237
- IL-7 inhibits the osteogenic differentiation of Periodontal ligament stem cells, possibly through inactivation of the mitogen-activated protein kinase (MAPK) signaling pathway. PMID: 27579861
- A study shows that IL-7 restores T Lymphocyte immunometabolic failure in septic shock patients through mTOR activation. PMID: 28724580
- In Colorectal Cancer (CRC), IL-7 levels were higher in patients with lymph node and distant metastases and with tumors located in the right colon. In adenomas, IL-7 elevation was exclusively associated with villous growth pattern, while in Inflammatory Bowel Disease (IBD), circulating IL-7 reflected the clinical activity of Crohn's disease and ulcerative colitis. PMID: 27866242
- Tuberculosis patients exhibited lower soluble IL-7R and higher IL-7 plasma concentrations compared to healthy contacts. PMID: 28582466
- CD56(bright) NK IL-7Ralpha expression negatively associates with HCV level, and IL-7-induced NK function is impaired during HCV and HIV infections. PMID: 28400540
- IL-7 plays a role in inducing epitope masking of the gammac protein in the IL-7 receptor signaling complex. PMID: 28127156
- Generalized CD8+ T-cell impairment in HCV infection is characterized by impaired IL-7-mediated signaling and survival, independent of CD127 expression. This impairment is more pronounced in the liver and may be associated with an increased potential for apoptosis. This generalized CD8+ T-cell impairment represents a significant immune dysfunction in chronic HCV infection that may alter patient health. PMID: 27315061
- Research reveals a novel role of IL-7 and IL-15 in maintaining human T cell function, providing an explanation for T cell dysfunction in humanized mice, and having significant implications for in vitro studies with human T cells. PMID: 27855183
- Studies demonstrate a significant association between SNPs in IL7 and Osteoarthritis (OA) in a Chinese Han population. PMID: 27235388
- IL-7 enhances functional T cell activity without causing significant functional imbalance between various T cell subsets. PMID: 28396296
- Research demonstrates that the IL-7/IL-7R axis promotes the invasion and migration of prostate cancer cells through activation of the AKT/NF-kappaB pathway and upregulation of MMP-3 and MMP-7 expression. PMID: 27611862
- A review explores the role of IL-7 in immunity and its involvement in the pathogenesis of neoplasia. PMID: 28314253
- Indian patients with primary Sjogren's syndrome exhibit higher salivary sL-selectin and IL-7 levels compared to healthy controls. PMID: 27620619
- Increased IL-7 secretion by mesenchymal stem cells (MSC) in the bone marrow may protect leukemic cells from imatinib-induced apoptosis through the JAK1/STAT5 signaling pathway. PMID: 27272942
- A study suggests for the first time that miR-181c negatively regulates the production of proinflammatory cytokines IL-7 and IL-17 in myasthenia gravis patients. PMID: 25962782
- Increased serum IL-7 is associated with adenoma. PMID: 25793917
- IL-7 provides negative feedback on its own signaling in T cells through endocytosis and degradation of its receptor, CD127. PMID: 26272555
- Studies observed highly significant reductions in the concentration of circulating interleukin (IL)-16, IL-7, and Vascular Endothelial Growth Factor A (VEGF-A) in encephalomyelitis/chronic fatigue syndrome patients. PMID: 26615570
- Observations suggest that IL-7 may play a role in the pathogenesis of Graves' disease and may be associated with its clinical activity. PMID: 26113403
- Elevated IL-7 and SCF levels persist for an extended period after double umbilical cord blood transplantation, and persistently high levels of these cytokines may correlate with poorer clinical outcomes. PMID: 26177551
- IL7 is primarily expressed in the infundibulum and suprabulb of the hair follicle. IL7 expression is increased in cutaneous T-cell lymphoma. PMID: 26479922
- Research identified that IL-7, along with the Akt/ mTOR signaling pathway, effectively modulates human Double-Negative T Cell-mediated suppression of allogeneic T cell responses. PMID: 26324773
- The IL-7/IL-17 axis mediates chronic pelvic pain in experimental autoimmune prostatitis and in patients. PMID: 25933188
- Considering the significant role IL-7 plays in lymphocyte proliferation, homeostasis, and survival, downregulation of CD127 by Tat likely plays a central role in immune dysregulation and CD4 T-cell decline. PMID: 25333710
- Decreased IL-7 in peripheral blood might be a consequence of the negative feedback of the pro-inflammatory function in ITP patients. PMID: 24750122
- Septic patients exhibited the lowest levels of IL-7. Patients with severe sepsis had higher levels of IL-7 compared to those with uncomplicated sepsis and septic shock. PMID: 25169828
- These observations provide evidence of a novel mechanism that allows cells to optimally utilize IL-7. PMID: 25870237
- Blocking IL-7 in hMSCs-lymphocytes co-cultures increased lymphocyte apoptosis. Furthermore, it was demonstrated that hMSCs are capable of producing this interleukin. PMID: 25184791
- Data indicate that high plasma levels of IL-7 in the early post-transplant period are predictive of slow T cell reconstitution, an increased risk of acute graft-versus-host disease, and higher mortality following hematopoietic stem cell transplantation. PMID: 25263171
- IL-7 elevates miR-124 to decrease the expression of splicing regulator PTB and represses CD95 mRNA splicing. PMID: 25411246
- Results strongly suggest that IL-7/IL-7R prevents apoptosis by upregulating the expression of bcl-2 and downregulating the expression of bax. PMID: 24695377
- Data suggest that increased IFN-alpha activity may promote the loss of T cells by accelerating cell turnover and activation-induced cell death while decreasing T cell renewal by inhibiting the proliferative effect of IL-7. PMID: 25063872
- Diminished T-cell responsiveness to IL-7. PMID: 24585897
- Low-level transient antigenic stimuli during cART were not associated with changes in thymic function or the IL-7/CD127 system. PMID: 24820104
- IL-7 can significantly impact the sustained expansion and persistence of adoptively chimeric antigen receptor-redirected cytotoxic T lymphocytes. PMID: 24097874
- IL-23 does not induce IL-7 expression in microglia and astrocytes. PMID: 24224652
- Changes in IL-7 expression during different phases of Graves ophthalmopathy (GO) suggest that IL-7 may play a significant role in the pathogenesis of GO. PMID: 23188693
- These results suggest that ineffective responses to IL-7 may impair the transition to memory cells of naive CD4(+) T lymphocytes recognizing self-peptides in the context of strong costimulation. PMID: 23454917
- Data indicate a novel role for IL-7 as a potential autocrine mediator of lymphatic drainage. PMID: 23963040
- Data show that IL-7 negatively regulates Tregs. PMID: 23966629
Q&A
What is Interleukin-7 and what are its primary biological functions?
Interleukin-7 (IL-7) is a cytokine originally identified for its growth-promoting effects on progenitors of B cells. It plays vital roles in health maintenance and disease prevention, with congenital deficiency of IL-7 signaling leading to profound immunodeficiency. IL-7 primarily contributes to host defense by regulating the development and homeostasis of immune cells, including T lymphocytes, B lymphocytes, and natural killer (NK) cells . IL-7 signaling is essential for normal thymopoiesis and has been shown to maintain and restore T-cell numbers, increase T-cell diversity, boost T-cell function, and inhibit T-cell apoptosis .
How does IL-7 affect different immune cell populations?
| Cells | Effects of IL-7 Deficiency | Effects of IL-7 Treatment |
|---|---|---|
| Thymus | Decreased thymic cell count; Thymic involution | Increased thymic cell count; Recovery of thymic function |
| T cells | Inhibition of glucose metabolism; Cell atrophy; Impaired T-cell functions; Severe impairment of T lymphopoiesis; T-cell apoptosis | Restored T-cell numbers; Increased T-cell diversity; Enhanced T-cell function; Inhibited T-cell apoptosis; Promoted glucose metabolism; Prevention of T-cell atrophy |
| B cells | Blocked transition to pro-B cells; Impaired B differentiation potential; Impaired early B lymphopoiesis; B-cell apoptosis | Increased B-cell numbers; Facilitated transition of pro-B cells; Promoted B-cell survival; Increased antibody production |
IL-7 has distinct effects on different immune cell populations, regulating their development, survival, and function. In T cells, IL-7 promotes survival of both naïve and memory populations, while in B cells, it influences multiple developmental stages including commitment, survival, differentiation, and proliferation . IL-7 also regulates the recruitment of other leukocytes such as neutrophils and monocytes .
What are the optimal methods for producing recombinant human IL-7?
Recombinant human IL-7 (rhIL-7) can be effectively produced using bacterial expression systems, with Escherichia coli HMS174 (DE3) pLysS under the control of a T7 promoter being well-documented . The expression typically results in insoluble inclusion bodies that require several purification steps. The production process involves separating inclusion bodies from cellular debris by cross-flow filtration, followed by solubilization using 6 M guanidine HCl . This approach yields substantial quantities of protein that can be subsequently refolded and purified.
What purification techniques are most effective for obtaining biologically active IL-7?
Purification of biologically active rhIL-7 requires multiple chromatographic steps. First, denatured, monomeric rhIL-7 should be purified by size-exclusion chromatography using Prep-Grade Pharmacia Superdex 200 prior to refolding . Attempting to refold rhIL-7 from solubilized inclusion bodies without this prior purification step has proven unsuccessful . Correctly folded rhIL-7 monomer is then generated by statically refolding the denatured protein at a final concentration of 80-100 μg/ml in 100 mM Tris, 2 mM EDTA, 500 mM L-arginine, pH 9.0 buffer with 0.55 g/l oxidized glutathione at 2-8°C for at least 48 hours . The refolded protein is subsequently purified through a combination of hydrophobic interaction, cation-exchange, and size-exclusion chromatography, resulting in a final product with >95% purity .
How should the biological activity of purified recombinant IL-7 be evaluated?
The biological activity of purified rhIL-7 should be assessed using validated IL-7-dependent bioassays. A well-established method involves the pre-B-cell bioassay, where IL-7-dependent pre-B cells are used to measure the proliferative response to the purified cytokine . For rigorous quality control, multiple analytical methods should be employed, including SDS-PAGE with Coomassie brilliant blue staining, high-pressure size-exclusion chromatography (SEC-HPLC), and reverse-phase HPLC . Additionally, endotoxin levels should be measured to ensure they remain below 0.05 EU/mg for research involving primary cells or in vivo applications .
What are the critical parameters for storage and stability of recombinant IL-7?
While specific storage conditions aren't detailed in the provided search results, based on standard practices for recombinant proteins, purified IL-7 should typically be stored at -80°C for long-term stability, with aliquoting recommended to avoid freeze-thaw cycles. Working solutions can be maintained at 2-8°C for limited periods, similar to the temperature range used during the refolding process . Stability studies should be conducted to determine the specific shelf-life under various storage conditions.
How does IL-7 influence antiviral immune responses?
IL-7 exhibits potent pro-immune functions during viral infections, particularly in overcoming inhibitory immune pathways that characterize chronic viral infections. In experimental models using lymphocytic choriomeningitis virus (LCMV) clone 13 infection, therapeutic administration of IL-7 enabled viral clearance from spleen, liver, and other viral reservoirs after 3 weeks of treatment, while control animals remained chronically infected . IL-7 promotes antiviral immunity through multiple mechanisms, including increasing the numbers of virus-specific CD8+ T cells and enhancing their effector functions . While IL-7 treatment expands multiple immune cell populations, including B cells and non-virus-specific T cells, depletion experiments demonstrated that CD4+ and CD8+ T cells are specifically essential for IL-7-mediated viral clearance .
What experimental design considerations are important when studying IL-7 in viral infection models?
When designing experiments to investigate IL-7's role in viral infections, researchers should consider:
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Appropriate viral model selection (e.g., LCMV clone 13 for chronic infection studies)
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Timing of IL-7 administration (therapeutic versus prophylactic)
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Duration of treatment (3 weeks was effective in LCMV studies)
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Inclusion of proper controls (PBS-treated animals)
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Comprehensive immune cell analysis, including:
Cell depletion experiments are valuable for determining which immune cell populations are necessary for IL-7-mediated effects, as demonstrated in studies showing the essential role of both CD4+ and CD8+ T cells in viral clearance .
How do genetic variations in IL-7 impact immune checkpoint blockade therapy?
Genetic variations in IL-7 have been associated with the risk of immune-related adverse events (irAEs) in cancer patients receiving immune checkpoint blockade (ICB) therapy. In a study of 214 melanoma patients receiving ICB, researchers observed increased risk of severe irAEs in carriers of the minor allele of rs16906115, which is intronic to the IL-7 gene . This genetic variation was associated with altered B cell subset distributions, particularly an increase in high IL-7-expressing unswitched memory (USM) B cells and a trend toward fewer naive B cells . These findings suggest that IL-7 genetic variants may influence clinical outcomes and toxicity of immunotherapies, potentially through modulation of B cell populations and function.
What are the mechanisms by which IL-7 influences B cell development and maturation?
IL-7 influences B cell development through several mechanisms. Gene expression analysis has shown that IL-7 expression is anti-correlated with the naive immunoglobulin IGHD but is associated with the percentage of immunoglobulin chains carrying secondary divergent mutations, as observed in somatic hypermutation . Single-cell RNA sequencing of B cells from melanoma patients and healthy controls revealed that IL-7 expression varies across B cell subsets, being highest in unswitched memory (USM) and switched memory (SM) cells, intermediate in naive cells, and lowest in antibody-secreting cells (ASCs) . Interestingly, patient B cells showed significantly higher IL-7 expression compared to those from healthy controls across all subsets except ASCs . Carriers of the rs16906115 risk allele demonstrated increased IL-7 expression across all B cells and had significantly increased counts of high IL-7-expressing USM cells , suggesting that IL-7 genetic variations may affect B cell subset distribution and function.
How can IL-7 be integrated with other immunomodulators for enhanced therapeutic efficacy?
IL-7 can be strategically combined with other immunomodulators to enhance therapeutic efficacy. Research has demonstrated that when IL-7 is administered in the presence of IL-12, the diversity of intratumoral CD8+ T cells increases, and IL-12's function is augmented to promote clonality . This synergistic effect suggests that combination therapies involving IL-7 and other cytokines or immune modulators may provide enhanced therapeutic benefits compared to monotherapies. Researchers investigating such combinations should design experiments that carefully evaluate potential synergistic or antagonistic effects on different immune cell populations and functions.
What are the methodological considerations for studying IL-7's role in immune reconstitution?
When studying IL-7's role in immune reconstitution, researchers should consider:
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Model selection (aging, lymphopenia, immunodeficiency)
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Dosing regimens and duration of treatment
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Comprehensive immune phenotyping, including:
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T cell subset analysis (naive vs. memory)
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T cell receptor (TCR) diversity assessment
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B cell developmental stages
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Thymic output measurements
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Functional immune assays
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Research has shown that while IL-7 therapy alone in aged mice could not completely reverse thymic involution, it can accelerate recovery of thymic function . The multiple functions of IL-7 in T-cell lymphopoiesis have encouraged its application as a therapy for recovering T-cell numbers . Methodologically sound research in this area requires careful consideration of baseline immune status, treatment protocols, and comprehensive outcome measures.
How does IL-7 dependency differ between mouse and human immune systems?
One notable contradiction in IL-7 research concerns the species-specific differences in IL-7 dependency. While IL-7 is essential for murine B-cell development, human B cells appear to develop normally in the absence of IL-7 . This is evidenced by the different presentations of genetic immunodeficiencies affecting the IL-7 pathway. Gene mutations at the human γc locus lead to X-linked severe combined immunodeficiency with distinct B cell presentations compared to murine models . Researchers must carefully consider these species-specific differences when translating findings from mouse models to human applications, as the developmental requirements and responses to IL-7 may vary significantly.
What are the critical methodological challenges in IL-7 research and how can they be addressed?
Critical methodological challenges in IL-7 research include:
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Producing consistently active recombinant protein (requires specific refolding conditions and purification steps)
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Distinguishing direct versus indirect effects of IL-7 on different cell populations
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Translating findings between species models (mouse vs. human differences)
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Addressing variability in IL-7 receptor expression across immune cell populations
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Developing standardized assays for IL-7 bioactivity
These challenges can be addressed through rigorous experimental design, careful validation of reagents, use of multiple complementary methodologies, and where possible, parallel studies in both human and mouse systems to identify species-specific differences. The purification protocol involving sequential chromatographic techniques has been shown to produce highly pure, biologically active rhIL-7 suitable for research applications .
