<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 Mouse Stem Cell Factor (KITLG)

Z200505 by Applied Biological Materials is Recombinant Mouse Stem Cell Factor (SCF/KITLG), a CHO-expressed 18 kDa glycoprotein with &gt;95% purity, endotoxin &lt;1.0 EU/µg, and bioactivity confirmed at &lt;2.0 ng/mL in TF-1 cell proliferation — used for HSPC expansion, mast cell research, and c-Kit signaling studies. 100 µg.

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Recombinant Mouse Stem Cell Factor (KITLG/SCF) by Applied Biological Materials (ABM) is a tag-free, E. coli-expressed cytokine (18.9 kDa, ≥95% SDS-PAGE purity, &lt;1.0 EU/µg endotoxin, ED50 &lt;2.0 ng/mL in TF-1 assay), lyophilized from Tris/NaCl pH 8.0 — used for murine HSC expansion, mast cell differentiation, and c-Kit signaling research. Available in 10 µg, 100 µg, and 1 mg formats.

Recombinant Mouse Stem Cell Factor (KITLG), 10 µg

Recombinant Mouse Stem Cell Factor (KITLG), 100 µg

Recombinant Mouse Stem Cell Factor (KITLG), 1.0 mg

Recombinant Mouse THPO

Recombinant Mouse THPO by ABM: 19 kDa E. coli-expressed thrombopoietin (TPO), &gt;95% purity by SDS-PAGE, &lt;1.0 EU/µg endotoxin. Bioactivity ED50 &lt;1.0 ng/mL (MO7e cell proliferation). Supports megakaryocyte differentiation, platelet biology, HSC self-renewal, and c-Mpl/JAK2/STAT5 signaling research. Research use only.

Recombinant Mouse THPO, 10 µg

Recombinant Mouse THPO , 1.0 mg

Recombinant Mouse TNF

Recombinant Mouse TNF (TNF-alpha) Z200215 by ABM—tag-free, E. coli-expressed, 17 kDa, &gt;95% purity, specific activity ≥3.0 × 10⁷ units/mg, ED50 ≤0.05 ng/mL. Available from MBP INC.

Recombinant Mouse TNF, 50 µg

Recombinant Mouse TNF, 100 µg

Recombinant Mouse TNF, 1.0 mg

Recombinant Mouse VEGF

Z200575 by Applied Biological Materials is recombinant mouse VEGF 164aa expressed in E. coli, with purity >95% by SDS-PAGE, endotoxin <1.0 EU/µg by LAL, ED50 2–4 ng/mL in HUVEC proliferation assay, and tag-free lyophilized formulation in PBS pH 7.0.

Recombinant Mouse VEGF (164aa), 10 µg

Recombinant Mouse VEGF (164aa), 100 µg

Recombinant Mouse VEGF (164aa), 1.0 mg

Recombinant Mouse VEGF (120aa) by Applied Biological Materials (ABM) is an E. coli-expressed growth factor (28 kDa, &gt;95% SDS-PAGE purity, &lt;1.0 EU/µg endotoxin, ED50 &lt;0.05 ng/mL HUVEC proliferation assay), lyophilized from glycine-sucrose-glutamate buffer pH 4.5. UniProt Q00731. Available in 10 µg, 100 µg, and 1.0 mg formats.

Recombinant Mouse VEGF (120aa), 10 µg

Recombinant Mouse VEGF (120aa), 100 µg

Recombinant Mouse VEGF (120aa), 1.0 mg

Recombinant Porcine LIF

Recombinant Porcine LIF by Applied Biological Materials is a 20 kDa E. coli-expressed, tag-free cytokine (lyophilized from PBS pH 7.0) with &gt;95% purity by SDS-PAGE and endotoxin &lt;1.0 EU/µg — used for porcine ESC/iPSC maintenance, reproductive biology, and JAK/STAT3 signaling research. Available in 10 µg, 100 µg, and 1 mg formats. UniProt Q9GKZ8.

Recombinant Porcine LIF, 10 µg

Recombinant Porcine LIF, 100 µg

Recombinant Porcine LIF, 1.0 mg

Flyer

Brochure

Recombinant Rat CNTF

Recombinant Rat CNTF by Applied Biological Materials — E. coli-expressed neuroprotective cytokine with &gt;95% purity, ED50 2–10 ng/mL (TF-1 cells), and endotoxin &lt;1.0 EU/µg. Available in multiple sizes for neuroscience and JAK/STAT3 signaling research.

Recombinant Rat CNTF, 20 µg

Recombinant Rat CNTF, 100 µg

Recombinant Rat CNTF, 1.0 mg

Recombinant Rat CXCL1

Recombinant Rat CXCL1 Z300105 by ABM — 8 kDa E. coli, &gt;95% pure by SDS-PAGE, ED(50) &lt;0.05 ng/mL (Ovcar3 proliferation), CXCR2 neutrophil chemoattractant, &lt;1.0 EU/µg endotoxin. Aliases: CINC-1, Gro1. Ships from MBP INC to USA, Canada, and international labs.

Recombinant Rat CXCL1, 25 µg

Recombinant Rat CXCL1, 100 µg

Recombinant Rat CXCL1, 1.0 mg

Recombinant Rat CXCL2

Z300115 by Applied Biological Materials is a recombinant rat CXCL2 (MIP-2) expressed in E. coli, with purity >95% by SDS-PAGE, endotoxin <1.0 EU/µg by LAL, ED50 <0.5 ng/mL in HepG2 proliferation assay, and tag-free lyophilized formulation in PBS pH 7.4.

Recombinant Rat CXCL2, 20 µg

Recombinant Rat CXCL2, 100 µg

Recombinant Rat CXCL2, 1.0 mg

Recombinant Rat EGF

Recombinant Rat EGF by Applied Biological Materials (ABM) is a tag-free, E. coli-expressed epidermal growth factor (6.2 kDa, ≥95% SDS-PAGE purity, &lt;1.0 EU/µg endotoxin, ED50 &lt;0.5 ng/mL in NIH3T3 assay), lyophilized from PBS pH 7.5 — used for rat neural stem cell expansion, hepatocyte culture, EGFR signaling assays, and rat-derived organoid systems. Available in 100 µg and 1 mg formats.

Recombinant Rat EGF, 100 µg

Recombinant Rat EGF, 1.0 mg

Recombinant Rat Eotaxin (CCL11)

Recombinant Rat Eotaxin (CCL11) — Z300145 by Applied Biological Materials. E. coli-expressed, &gt;95% purity by SDS-PAGE, endotoxin &lt;1.0 EU/µg. Chemoattracts human eosinophils at 0.1–20 ng/mL via CCR3. Available in 20 µg, 100 µg, and 1.0 mg.