Biolegend, 571656, Recombinant Human IL-37b (IL-1F7b) (carrier-free), 100μg

IL-37, also known as IL-1F7, belongs to the IL-1 family. There are five isoforms generated by alternative splicing, identified as IL-37a to IL-37e. IL-37b is the largest isoform and IL-37a contains a unique N-terminal sequences, absent in other isoforms. IL-37 is exclusively expressed only in human cells, but not found in murine cells. IL-37 isoforms are expressed in a tissue-specific manner. Its expression is upregulated upon LPS stimulation as well as TLR agonists in human blood monocytes and macrophages, whereas it is downregulated by IL-12, IL-32 and combination of GM-CSF and IL-4. IL-37 has been shown to translocate to the nucleus upon LPS treatment. IL-37 is a broad anti-inflammatory cytokine. Upon IL-37 administration, wild-type mice are protective from experimental models of endotoxin shock, acute lung and spinal cord injury, asthma and colitis. IL-37a and IL-37b inhibits LPS-mediated pro-inflammatory cytokine production in M1-differentiated macrophages and dendritic cells via IL-18Rα and SIGIRR/IL-1R8. IL-37b stimulation enhances the suppressive activity of CD4 + CD25 + Treg cells, along with upregulation of CTLA-4 and Foxp3 expression and increase of TGF-β1 production. Both IL-37b and IL-37d negatively regulates immune responses in a Smad3-dependent manner.
100μg
Source: Human IL-37 isoform b, amino acid (Val46 - Asp218) (Accession: # Q9NZH6), was expressed in E.coli.
Molecular Mass: The 173 amino acid recombinant protein has a predicted molecular mass of approximately 19.3 kD. The DTT-reduced and non-reduced protein migrates at approximately 15 - 27 kD by SDS-PAGE. The N-terminal amino acid is Val.
Purity: ≥ 95%, as determined by Coomassie stained SDS-PAGE.
Formulation: 0.22 µm filtered protein solution is in PBS, pH 7.4, 1mM DTT
Endotoxin Level: Less than 0.1 EU per µg protein as determined by the LAL method.
Concentration: 25 µg size is bottled at 200 µg/mL. 100 µg size and larger sizes are lot-specific and bottled at the concentration indicated on the vial. To obtain lot-specific concentration and expiration, please enter the lot number in our Certificate of Analysis online tool.
Storage & Handling: Unopened vial can be stored between 2°C and 8°C for up to 2 weeks, at -20°C for up to six months, or at -70°C or colder until the expiration date. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C or colder. Stock solutions can also be prepared at 50 - 100 µg/mL in appropriate sterile buffer, carrier protein such as 0.2 - 1% BSA or HSA can be added when preparing the stock solution. Aliquots can be stored between 2°C and 8°C for up to one week and stored at -20°C or colder for up to 3 months. Avoid repeated freeze/thaw cycles.
Activity: Recombinant human IL-37b inhibits LPS-induced mouse IL-6 production by RAW 264.7 cells in a dose-dependent manner. The ED50 for this effect is 1 – 10 µg/mL.
Application: Bioassay
Application Notes: BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue-ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are validated in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at [email protected].
Structure: Monomer
Distribution: Isoform B are expressed in kidney, testis, colon, placenta, lung and lymph node; NK cells, stimulated B cells, keratinocytes, epithelial cells; nucleus, secreted, cytosol
Function: IL-37b plays a crucial role in suppressing immune responses. IL-37b antagonizes IL-18-mediated function
Interaction: SMAD3, IL-18Rα, IL-18Rβ, IL-18BP
Bioactivity: Measured by its ability to bind human IL-18Rα-Fc
Cell Type: B cells, Epithelial cells, NK cells
Biology Area: Adaptive Immunity, Immuno-Oncology, Innate Immunity, Signal Transduction
Molecular Family: Cytokine/Chemokine Receptors, Cytokines/Chemokines, Innate Immune Signaling
Antigen References: Smith DE, et al. 2000. J Biol Chem. 275:1169-75. Li S, et al. 2014. Proc Natl Acad Sci USA. 112:2497. Wang DW, et al. 2016. Sci Rep. 6:38955. Dinarello CA, et al. 2016. Eur J Immunol. 46:1067-81. McNamee EN, et al. 2011. Proc Natl Acad Sci USA. 108:16711-6. Zhao M, et al. 2018. Cell Death Dis. 9:582. Nold MF, et al. 2010. Nat Immunol. 11:1014-22. Wang L, et al. 2018. Oncol Lett. 15: 4711-47. Bulau AM, et al. 2014. Proc Natl Acad Sci USA. 111:2650. Afonina IS, et al. 2015. Immunity. 42:991-1004.
Gene ID: 27178
UniProt: View information about IL-37b on UniProt.org
Regulatory Status: RUO
Other Names: Interleukin-37, FIL1 zeta, Interleukin-1 family member 7, IL-1F7, Interleukin-1 homolog 4, IL-1H, IL-1H4, IL-1 zeta, Interleukin-1-releated protein, IL-1RP1
Q: Why choose BioLegend recombinant proteins?
A: • Each lot of product is quality-tested for bioactivity as indicated on the data sheet.
     • Greater than 95% Purity or higher, tested on every lot of product.
     • 100% Satisfaction Guarantee for quality performance, stability, and consistency.
     • Ready-to-use liquid format saves time and reduces challenges associated with reconstitution.
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Q: How does the activity of your recombinant proteins compare to competitors?
A: We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!
Q: What is the specific activity or ED50 of my recombinant protein?
A: The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.
Q: Have your recombinants been tested for stability?
A: Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.
Q: Does specific activity of a recombinant protein vary between lots?
A: Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.
Q: How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
A: Use formula Specific activity (Units/mg) = 10^6/ ED50 (ng/mL)