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<h2 data-section-id="pdko8n" data-start="0" data-end="50">What are recombinant proteins for cell culture?</h2>
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Recombinant proteins for cell culture are biologically active growth factors, cytokines, and signaling molecules produced using recombinant DNA technology to control specific cellular functions in vitro. Growth factors such as FGF (fibroblast growth factor), EGF (epidermal growth factor), and TGF-&beta; (transforming growth factor beta) regulate cell growth, proliferation, survival, and differentiation. Cytokines including IL-2, IL-7, IL-15, and IL-21 influence immune cell activation, expansion, and function. These proteins are widely used in serum-free and chemically defined media, stem cell and iPSC culture, immune cell expansion, organoid development, hybridoma production, and cell and gene therapy workflows where precise control over cellular signaling is required.
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<h2 dir="ltr">What you will find:</h2>
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<ul>
<li>Includes cytokines, chemokines, growth factors, and signaling proteins to support proliferation, differentiation, and maintenance of&nbsp;mammalian cells</li>
<li>Rat, human, and mouse recombinant proteins compatible with translational research models and diverse mammalian cell culture&nbsp;</li>
<li>Optimizing cell metabolic activity, signalling pathways, and experimental reproducibility in vitro using recombinant proteins&nbsp;</li>
<li>Suitable for organoid development, expansion of cells, activation of immune cells, neuronal studies, and protein expression workflow optimization.</li>
</ul>
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<h2 data-section-id="4x59d8" data-start="1050" data-end="1118">How to choose recombinant proteins, cytokines, and growth factors</h2>
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Quality grade: RUO vs. preclinical vs. GMP
Research-use-only (RUO) proteins are suitable for most academic and industrial research applications. Preclinical-grade proteins provide enhanced documentation and quality control for studies supporting clinical development. GMP-grade proteins are manufactured under controlled quality systems with complete traceability and lot-to-lot bioactivity verification, making them appropriate for cell therapy, gene therapy, and other regulated applications.
Expression system and post-translational modifications
The production system can significantly affect protein activity. HEK293 and other mammalian expression systems preserve native human post-translational modifications such as glycosylation and phosphorylation, which are often necessary for full biological function. Bacterial expression systems such as E. coli may offer lower cost and higher yields but cannot reproduce many of these modifications.
Carrier-free formulation
Carrier-free recombinant proteins are formulated without stabilizing proteins such as bovine serum albumin (BSA). This eliminates potential experimental interference from carrier proteins and supports serum-free, animal-component-free, and GMP-compatible workflows. Carrier-free formulations are especially important when studying sensitive signaling pathways or developing clinical manufacturing processes.
Endotoxin level and purity
Endotoxins can stimulate inflammatory responses and alter cell behavior, particularly in immune cell cultures. For T-cell expansion, stem cell culture, and other sensitive applications, low-endotoxin or endotoxin-free proteins with documented purity above 95% are preferred to ensure reproducible results.
Stability format: standard vs. thermostable
Standard recombinant proteins gradually lose activity during prolonged incubation at 37&deg;C. Thermostable variants, such as engineered FGF2 formulations, maintain biological activity for longer periods and reduce the need for frequent media supplementation. These products can improve workflow efficiency in stem cell maintenance and differentiation protocols.
Storage and reconstitution
Lyophilized recombinant proteins offer extended shelf life and are typically stored frozen until use. After reconstitution, proteins should be aliquoted into single-use portions whenever possible to minimize repeated freeze-thaw cycles that can reduce activity. Proper storage conditions vary by product and should follow the manufacturer's recommendations.
<h2 data-section-id="rxnuuy" data-start="3659" data-end="3704">&nbsp;</h2>
<h2 data-section-id="1fljvas" data-start="4451" data-end="4476">Specifications context</h2>
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Modern recombinant cytokines and growth factors are available in a wide range of formats including carrier-free, low-endotoxin, animal-component-free, and GMP-grade formulations. Many GMP-grade cytokines such as IL-2, IL-7, IL-15, and IL-21 undergo lot-specific bioactivity testing using validated reference standards to ensure consistent biological performance. Mammalian-cell-expressed proteins are increasingly preferred for applications requiring native structure and maximum biological activity.
As of 2026, carrier-free, low-endotoxin recombinant proteins produced in mammalian expression systems have become the preferred choice for stem cell culture, immune cell expansion, organoid development, and advanced biomanufacturing workflows.
For basal media used alongside recombinant proteins, see Classic Media. For additional supplementation reagents, see Cell Culture Supplements &amp; Additives. Browse Mammalian Cell Culture for the broader category.
<a href="https://mbpinc.net/contact-us">Contact the expert team</a> at MBP today and get optimized recombinant proteins for your lab.

Recombinant Proteins

MSDS

Growth Factor-eFlyer

Growth Factors and Cytokines-Brochure

Growth Factors and Cytokines-FAQ

Role of Growth Factors in Cell Differentiation-Poster

Recombinant Human IL31

Z100525 by ABM — Recombinant Human IL-31, 18 kDa, tag-free, expressed in E. coli. Purity &gt;95% by SDS-PAGE, endotoxin &lt;1.0 EU/µg, STAT3 activation confirmed. Available in 10 µg and 1.0 mg.

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Recombinant Human IL31, 10 µg

Recombinant Human IL31, 1.0 mg

Recombinant Human IL33

Z100535 by ABM — Recombinant Human IL-33, 18 kDa, tag-free, expressed in E. coli. Purity &gt;95% by SDS-PAGE, endotoxin &lt;1.0 EU/µg, ED50 ≤0.03 ng/mL (D10S proliferation). Available in 10 µg, 100 µg, and 1.0 mg.

Recombinant Human IL33, 10 µg

Recombinant Human IL33, 100 µg

Recombinant Human IL33, 1.0 mg

Recombinant Human IL36A

Recombinant Human IL36A (IL-1F6), Z101865 by ABM. Expressed in E. coli; 17.4 kDa; &gt;95% purity; tag-free. Supplied lyophilized in 20 mM Tris pH 8.0, 200 mM NaCl. Reconstitute in sterile PBS + ≥0.1% BSA/HSA to ≥10 µg/mL. For epithelial inflammation and IL-36 pathway research.

Recombinant Human IL36A, 20 µg

Recombinant Human IL36A, 100 µg

Recombinant Human IL36A, 1.0 mg

Recombinant Human IL36B

Recombinant Human IL36B (Z102465) by ABM. IL-1F8, 17.5 kDa, >95% purity, E. coli expressed. Supports psoriasis, skin barrier immunity, and IL-36 pathway research.

Recombinant Human IL36B, 10 µg

Recombinant Human IL36B, 100 µg

Recombinant Human IL36B, 1.0 mg

Recombinant Human IL36G

Recombinant Human IL36G (Z102215) by ABM. IL-1F9, 18.9 kDa, >95% purity, E. coli expressed. ED50 <0.5 ng/mL. Supports psoriasis, skin barrier immunity, and IL-36 pathway research.

Recombinant Human IL36G, 10 µg

Recombinant Human IL36G, 100 µg

Recombinant Human IL36G, 1.0 mg

Recombinant Human IL36RN (IL1F5)

Z102645 by Applied Biological Materials is recombinant human IL36RN (IL-36Ra, IL1F5), a member of the IL-1 superfamily expressed in E. coli with >95% purity. IL36RN competitively antagonizes IL-36α, IL-36β, and IL-36γ signaling through IL-36R (IL1RL2). Loss-of-function IL36RN mutations underlie generalized pustular psoriasis. Lyophilized from Tris/NaCl/KCl buffer; reconstitute in sterile distilled water. Available from MBP for IL-36 pathway, psoriasis, and skin inflammation research.

Recombinant Human IL36RN (IL1F5), 20 µg

Recombinant Human IL36RN (IL1F5), 100 µg

Recombinant Human IL36RN (IL1F5), 1.0 mg

Recombinant Human IL37 (IL1F7)

Recombinant human IL-37 / IL1F7 (Z102085) by ABM — 19.5 kDa, E. coli, &gt;95% purity, tag-free. Anti-inflammatory IL-1 family cytokine for innate immunity and SIGIRR signaling research.

Recombinant Human IL37 (IL1F7), 10 µg

Recombinant Human IL37 (IL1F7), 100 µg

Recombinant Human IL37 (IL1F7), 1.0 mg

Recombinant Human IL4

Z100545 by Applied Biological Materials is a recombinant human IL-4 expressed in E. coli, supplied lyophilized at &gt;95% purity with an exceptionally potent ED50 &lt;0.2 ng/ml in TF-1 proliferation assays. IL-4 drives Th2 polarization, IgE class switching, monocyte-derived DC generation (with GM-CSF), and M2 macrophage polarization via JAK1/JAK3/STAT6 signaling.

Recombinant Human IL4, 10 µg

Recombinant Human IL4, 100 µg

Recombinant Human IL4, 1.0 mg

Recombinant Human IL5

Z102625 by Applied Biological Materials (ABM) is a tag-free recombinant human Interleukin-5 (IL-5) protein expressed in E. coli, with greater than 95% purity by SDS-PAGE and endotoxin below 1.0 EU/µg. The 13 kDa monomeric protein is supplied as lyophilized powder for eosinophil biology, hematopoietic progenitor expansion, and B cell differentiation research.

Unit Quantity

Recombinant Human IL6

Z100555 by Applied Biological Materials is E. coli-expressed recombinant human Interleukin-6 (IL-6 / BSF-2 / IFNB2), a 21 kDa non-glycosylated pleiotropic cytokine supplied as lyophilized powder. Purity &gt;95% by SDS-PAGE; endotoxin &lt;1.0 EU/µg by LAL. Bioactivity confirmed by TF-1 cell proliferation (ED50 0.5–1 ng/mL). Available in 20 µg, 100 µg, and 1.0 mg; contact MBP for pricing.

Recombinant Human IL6, 20 µg

Recombinant Human IL6, 100 µg

Recombinant Human IL6, 1.0 mg

Recombinant Human IL7

Recombinant Human IL-7 (Interleukin-7), catalog Z100975 by ABM. E. coli-expressed, 17.7 kDa, >95% purity, lyophilized. Bioactive with ED50 &lt;0.5 ng/mL. Essential lymphocyte cytokine. Endotoxin &lt;1.0 EU/µg.

Recombinant Human IL7, 10 µg

Recombinant Human IL7, 100 µg

Recombinant Human IL7, 1.0 mg

Recombinant Human IL8 (72aa)

Recombinant Human IL8 (72aa, CXCL8), Z101605 by ABM. Expressed in E. coli; 8.3 kDa; &gt;95% purity; tag-free. ED50 &lt;0.5 ng/mL (endothelial proliferation). Lyophilized in PBS pH 7.0. For neutrophil chemotaxis and CXCR1/CXCR2 research.