Our mission is to provide the highest quality research products available for you to get reliable results quickly and easily. In addition to being a leading provider of high quality, affordable reagents for applications such as multicolor flow cytometry, BioLegend also offers an extensive selection of purified human, mouse, and rat recombinant proteins, including cytokines, chemokines, and growth factors.

Contact our sales team regarding samples, or special pricing on bulk quantities!

Our expanding catalog of recombinant proteins includes cytokines, chemokines, growth factors, enzymes, adhesions molecules, and more. These proteins are tested in a variety of bioassays to ensure bioactivity. For studies that are particularly sensitive to contamination with mammalian pathogens, we also offer animal-free versions of many of our recombinant proteins. Like our carrier-free formats, these proteins do not contain any carrier proteins; however, the animal-free products are produced in animal-free media with equipment that is free of all animal components. Browse our recombinant proteins groups below!

Our growing portfolio of recombinant proteins includes human, mouse, and rat proteins that can be used for bioassays in diverse research areas including immunology, neurobiology, stem cell research, cancer research, glycobiology, and more!



  • >95% pure
  • Expressed in mammalian, E.coli, or insect protein expression systems
  • No reconstitution necessary (for most carrier-free formats), provided in a liquid format
  • Validated in-house through bioassays to ensure bioactivity and reproducibility
  • Compare favorably against competitors' products
  • Competitively priced and discounted for bulk orders
  • Flexible, custom recombinant protein production
  • Both carrier-free and animal-free formats available

Common Uses of our Recombinant Proteins:

  • Cell culture
  • Cell activation
  • Cell expansion
  • Differentiation
  • Enzymatic cleavage
  • Polarization
  • Cytokine production
  • Inhibition
  • Cytotoxicity
  • Chemotaxis
  • Cell Signaling Activation
  • Western blot controls

Download the Recombinant Proteins Brochure.

Have more questions on our products? Check the recombinant protein FAQs or contact Tech Service.



Stringent Quality Testing

To ensure that we deliver the highest quality products, our recombinant proteins undergo rigorous testing before they reach your hands.

Product Purity and Quantitation Testing table


Acceptance criteria for majority of proteins is greater than 95%
Quantity UV spec, SDS-PAGE
10 and 25 μg sizes are bottled at 0.1 or 0.2 mg/ml 
100 μg and larger sizes are bottled at a lot-specific concentration
Molecular Weight DTT-reduced and non-reduced SDS-PAGE
Mass Spec (for E.coli expressed proteins)
Microbiological Control 0.2 μm filtration prior to bottling
Endotoxin level Endotoxin tested by the LAL (Limulus Amoebocyte Lysate) assay 
Less than 0.1 ng per μg protein or 1 EU per μg protein


Recombinant proteins were run in SDS-PAGE under either DTT-reducing or non-reducing conditions, as indicated, to confirm purity of the recombinant protein was >95%.

Recombinant proteins run on an LC-Agilent 6230 Time-of-Flight Mass Spectrometer. Deconvoluted mass spectrums shown with predicted and observed molecular weights indicated.

Functional Testing

Based on the expected function of the protein, we test our recombinants in bioassays for quality control, to characterize the protein, and measure its activity. These bioassays include: proliferation, chemotaxis, neurite outgrowth, enzymatic activity, cytotoxicity, cytokine production, adhesion, and differentiation assays.

Recombinant Human OMG (Carrier-Free)



Figure A. 300 ng of human OMG, immobilized as a 3 μL droplet on a nitrocellulose-coated plate, completely inhibits neurite outgrowth of E13 chick DRG neurons induced by laminin substrate. Figure B. 3 μL droplet of buffer control (PBS) on a nitrocellulose-coated plate shows no inhibition of neurite outgrowth of E13 chick DRG neurons induced by laminin substrate.

Stability Testing

Our recombinants are stability tested at different temperatures and time intervals to determine optimal storage, handling, and shipping conditions. Our testing shows that most of our recombinant proteins are able to withstand room temperature (RT) and 37°C for a week without losing activity. In addition, most recombinants are able to withstand four freeze-thaw cycles without losing activity.

Recombinant proteins were aliquoted in PBS pH 7.2 at 0.2 mg/ml. One aliquot was frozen and thawed four times (4x freeze/thaws), one was kept at RT, and one was kept at 37°C for one week. All samples were tested for bioactivity as compared to a control stored at 4°C.

Competitor and Internal Control Testing

To ensure you have full confidence when using our recombinant proteins, we internally compare new lots with previous lots for consistency. In addition, we also test our products against those available from competitors.

Recombinant Rat EGF (carrier-free)



Recombinant rat EGF induces a cytotoxic effect on human A431 epidermoid carcinoma cell line in a dose- dependent manner. BioLegend’s protein was compared side-by-side to the leading competitor’s equivalent product.

Recombinant Mouse M-CSF


Recombinant mouse M-CSF induces proliferation of M-NFS-60 cells in a dose-dependent manner. A new lot of protein was compared side-by-side to an internal gold standard.

Product Authors Journal Year Vol/Page Pubmed
Recombinant Mouse CCL3 (MIP-1α) (carrier-free) Popova T, et al. PLoS One 2016 11: 0163163 Link
Recombinant Human CD40L (TNFSF5) (carrier-free) Sayin I, et al. J Exp Med 2018 7:40286 Link
Recombinant Mouse CX3CL1 (Fractalkine) (carrier-free) Dorfman M, et al. Nat Commun 2017 8:14556 Link
Recombinant Mouse CXCL1 (KC) (carrier-free) Kamp M, et al. PLoS One 2016 11: 0163750 Link
Recombinant Human CXCL10 (IP-10) (ELISA Std.) Ramirez L, et al. J Leukoc Biol 2014 96:1055 Link
Recombinant Mouse CXCL10 (IP-10) (carrier-free) Pfeiffer A J Gen Virol 2015 96:1328 Link
Recombinant Human CXCL10 (IP-10) (carrier-free) Sek A, et al. PLoS One 2015 10: 0133266 Link
Recombinant Human CXCL10 (IP-10) (carrier-free) Li Y, Kaneda T Sci Rep 2016 6: 25077 Link
Recombinant Human EGF (carrier-free) Tam A, et al. Sci Rep 2019 9:3353 Link
Recombinant Mouse EGF (carrier-free) Pei G, et al. Mol Biol Cell 2015 26: 3061-3070 Link
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