<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>
&nbsp;
<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 Rat FGF2

Recombinant Rat FGF-2 (bFGF) by ABM: 16 kDa E. coli-expressed growth factor, &gt;95% purity by SDS-PAGE, &lt;1.0 EU/µg endotoxin. Bioactivity ED50 &lt;1.0 ng/mL (3T3 thymidine uptake). Supports stem cell culture, angiogenesis, FGFR signaling, and neurogenesis research. Research use only.

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Recombinant Rat FGF2, 50 µg

Recombinant Rat FGF2, 1.0 mg

Recombinant Rat G-CSF (CSF3)

Z300185 by Applied Biological Materials (ABM) is a recombinant rat G-CSF (CSF3) expressed in E. coli, 21.8 kDa, tag-free, with greater than 95% purity by SDS-PAGE and endotoxin below 1.0 EU/µg. Supports neutrophil and granulocyte differentiation and hematopoiesis research in rat systems. Available in 5 µg and 100 µg sizes.

Recombinant Rat G-CSF (CSF3), 5 µg

Recombinant Rat G-CSF (CSF3), 100 µg

Recombinant Rat GRO gamma (CXCL3)

Recombinant Rat GRO gamma (CXCL3) by Applied Biological Materials is 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.

Recombinant Rat GRO gamma (CXCL3), 10 µg

Recombinant Rat GRO gamma (CXCL3), 100 µg

Recombinant Rat GRO gamma (CXCL3), 1.0 mg

Recombinant Rat IFNG

Recombinant Rat IFNG Z300015 by ABM — 16 kDa E. coli, &gt;95% pure by SDS-PAGE, ED(50) &lt;1.0 ng/mL with specific activity &gt;1.0×106 units/mg (L929/EMC virus assay), &lt;1.0 EU/µg endotoxin. Ships from MBP INC to USA, Canada, and international labs.

Recombinant Rat IFNG, 100 µg

Recombinant Rat IFNG, 1.0 mg

Recombinant Rat IGF1

Recombinant Rat IGF1 by Applied Biological Materials (ABM) is a tag-free, E. coli-expressed growth factor (8 kDa, ≥95% SDS-PAGE purity, &lt;1.0 EU/µg endotoxin, specific activity ≥1.0×10⁶ units/mg, ED50 ≤1.0 ng/mL), lyophilized from PBS pH 7.4 — used for rat primary neuron culture, skeletal muscle research, and IGF1R/PI3K pathway studies. Available in 50 µg, 250 µg, and 1 mg formats.

Recombinant Rat IGF1, 50 µg

Recombinant Rat IGF1, 250 µg

Recombinant Rat IGF1, 1.0 mg

Recombinant Rat IL10

Z300025 by Applied Biological Materials (ABM) is a recombinant rat IL-10 protein expressed in E. coli, with greater than 95% purity by SDS-PAGE, endotoxin below 1.0 EU/µg, and an ED50 below 12 ng/mL in T cell suppression assays. Supplied tag-free as lyophilized powder.

Recombinant Rat IL10, 20 µg

Recombinant Rat IL10, 1.0 mg

Flyer

Brochure

Recombinant Rat IL13

Recombinant Rat IL-13 by ABM: 12 kDa E. coli-expressed Th2 cytokine, &gt;95% purity by SDS-PAGE, &lt;1.0 EU/µg endotoxin. Bioactivity ED50 &le;2.0 ng/mL (TF-1 cell proliferation). Supports allergy, asthma, STAT6 signaling, and fibrosis research. Research use only.

Recombinant Rat IL13, 10 µg

Recombinant Rat IL13, 1.0 mg

Recombinant Rat IL17

Z300175 by Applied Biological Materials is recombinant rat IL-17A expressed in E. coli, with purity >95% by SDS-PAGE, endotoxin <1.0 EU/µg by LAL, bioactivity confirmed by IL-6 induction in murine 3T3 cells, and tag-free lyophilized formulation in PBS pH 7.5.

Recombinant Rat IL17, 25 µg

Recombinant Rat IL17, 1.0 mg

Recombinant Rat IL1B

Z300075 by Applied Biological Materials is recombinant rat IL-1 beta expressed in E. coli, with purity >95% by SDS-PAGE, endotoxin <1.0 EU/µg by LAL, ED50 ≤2.0 pg/mL in D10S thymidine uptake assay, and tag-free lyophilized formulation in PBS pH 7.

Recombinant Rat IL1B, 10 µg

Recombinant Rat IL1B, 100 µg

Recombinant Rat IL1B, 1.0 mg

Recombinant Rat IL2

Recombinant Rat IL2 (Z300195) by ABM — 15.6 kDa E. coli-expressed T-cell growth factor, >95% pure, ED50 0.04–0.2 ng/mL. Order from MBP INC.

Recombinant Rat IL2, 5 µg

Recombinant Rat IL2, 100 µg

Recombinant Rat IL2, 1.0 mg

Recombinant Rat IL20

Recombinant Rat IL-20 Z300165 by ABM: 16 kDa, E. coli expressed, tag-free, >95% purity by SDS-PAGE, endotoxin &lt;1.0 EU/µg (LAL). ED50 &lt;0.6 ng/mL in BaF3 cell proliferation assay. Lyophilized from PBS pH 7.5; supplied as 10 µg. IL-10 family cytokine (UniProt B8K1Y1) for STAT3 signaling, keratinocyte proliferation, and skin inflammation research.

Recombinant Rat IL20, 10 µg

Recombinant Rat IL20, 1.0 mg

Recombinant Rat IL3

Recombinant Rat IL3 — Z300205 by Applied Biological Materials. E. coli-expressed, tag-free, &gt;95% pure by SDS-PAGE, 15.9 kDa, endotoxin &lt;1.0 EU/µg. ED50 1.0–5.0 ng/mL. Supports hematopoietic progenitor expansion and mast cell culture.

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