Key Benefits Our Recombinant Proteins Offer to Customers
- High Levels of Biological Activity: The biological activity of each protein is tested in an appropriate biological system to confirm that it meets our strict QC activity parameters before it is released to market.
- Lot-to-Lot Consistency: Minimal lot-to-lot variability is ensured by maintaining consistent manufacturing conditions and testing each new lot side-by-side with previous lots and with a master lot, so you don’t have to worry whether results will be reproducible over time.
- High Purity: The majority of our proteins have >95% purity and a guaranteed industry-leading endotoxin level of <0.1 EU/ug by the LAL method.
- Long-term Stability: The bioactivity and physical state of our proteins are monitored through multiple freeze/thaw cycles, so you can be confident that your protein will be stable over long periods of time. All proteins are shipped lyophilized or in specially optimized formulations to ensure that they reach you in perfect condition.
- Comprehensive Selection: Our catalog includes over 5,000 biologically active recombinant and natural proteins spanning 35 species, and more than 10,000 non-catalog proteins for multiple different research areas, allowing you to easily find the proteins that you need.
- Multiple Host Expression Systems, Tags, and Labels: Our proteins are produced in a variety of host expression systems and are either untagged or include a biotin, Fc, or His tag, or a fluorescent label to meet different experimental needs.
- Seamless Transition from RUO to GMP: Our Animal-free and GMP-grade proteins frequently originate from the same clone, sequence, and expression system as our traditional research-grade proteins, making the transition from basic research into process development and clinical manufacturing as efficient and seamless as possible.
- Bulk Proteins at Discounted Prices: We have the capacity and the expertise to scale up the production of any protein and we offer economical pricing on bulk orders.
- Custom Protein Capabilities: If you don’t see the protein that you need on our website, we offer custom protein services. From scratch protein development to customizing a protein from our catalog, our custom services team will work with you to create the product that fits your experimental needs.
- Custom Bottling Options: If your research requires a special formulation or size, custom bottling options are available.
- Expert Customer Support Assistance: Almost all of our proteins are manufactured in-house, allowing us to maintain complete control over the quality of our products. If you have any questions about our products, our protein scientists and highly trained technical service team are always available to assist you.
Featured Recombinant Protein Products

Cytokines and Growth Factors
Cytokines and Growth Factors
• The most reliable source of cytokines and growth factors for immune cell, stem cell, and neural cell culture
• An unparalleled selection of recombinant proteins for studying interleukins, interferons, chemokines, adipokines, and TNF superfamily members
• The highest quality, most consistent cytokines and growth factors for organoid cell culture
• Bulk and custom protein services to meet every researcher’s need

Immune Checkpoint Proteins
Immune Checkpoint Proteins
• Proteins for studying common targets including PD-1, PD-L1, and CTLA-4, and emerging targets such as TIGIT, LAG-3, Butyrophilins, and LILR family members
• Multiple tags available including Fc, His, and an expanding selection of Avi-tag biotinylated proteins
• Proteins for a range of different species including many non-human primate proteins with over 80 cynomolgus and rhesus monkey immune checkpoint proteins
• Bioactivity validated using a variety of different assays including cell proliferation or cytokine secretion assays, functional ELISA, or SPR

Proteins for Coronavirus Research
Proteins for Coronavirus Research
• Our catalog includes a large selection of SARS-CoV-2 Spike proteins that exhibit high levels of ACE-2 binding activity and purity
• Multiple SARS-CoV-2 Spike mutant proteins are available, including the Alpha, Beta, Gamma, Delta, Lambda, and Mu variants
• Rigorous lot-to-lot consistency testing ensures each new lot displays the same level of bioactivity and purity as previous lots
• Scalable production capabilities to meet manufacturing needs
Avi-tag and Amine-Labeled Biotinylated Proteins
Avi-tag and Amine-Labeled Biotinylated Proteins
• Avi-tag biotinylated proteins incorporate a single biotin within the Avi-tag to provide consistent labeling and uniform protein orientation for binding assays
• Amine-labeled biotinylated proteins incorporate multiple biotins per molecule, allowing for high signal strength and binding efficiency
• All R&D Systems™ biotinylated proteins are rigorously tested to ensure that they exhibit the same level of bioactivity as the unlabeled protein and exhibit minimal lot-to-lot variability
Fluorokines™ Fluorescent-Labeled Proteins
Fluorokines™ Fluorescent-Labeled Proteins
• Fluorokines are highly specific and allow target molecules to be directly stained and detected by flow cytometry
• They are conjugated to Alexa Fluor® or Atto dyes, which offer intense fluorescence and excellent photostability
• Fluorokines undergo rigorous testing to ensure specificity, bioactivity, and lot-to-lot consistency
• Fluorokines are compatible with antibody panels for multi-color flow cytometry
GMP Proteins
GMP Proteins
- Extensive documentation for traceability of source
- Rigorous lot-to-lot consistency testing against a master lot
- Additional quality control testing and quality assurance review
- Request a GMP protein sample
- Request a video tour of our GMP animal-free manufacturing facility
R&D Systems Recombinant Proteins Are Frequently More Active than Leading Competitors' Proteins

R&D Systems Recombinant Human Thrombopoietin/Tpo Displays Higher Activity than Leading Competitors’ Thrombopoietin Proteins. The bioactivity of R&D Systems Recombinant Human Thrombopoietin (Catalog # 288-TPE; orange line) or recombinant human Thrombopoietin/Tpo from two different competitors (green and purple lines) was assessed by measuring the ability of the proteins to stimulate the proliferation of the MO7e human megakaryocytic leukemic cell line. The ED50 for this effect for R&D Systems Recombinant Human Thrombopoietin is 0.05-0.5 ng/mL, which is over 2-fold more active than the two competitors’ proteins.

R&D Systems Recombinant Human FGF basic/FGF-2 Displays Higher Activity than a Leading Competitor’s Recombinant Human FGF-2 Protein. The NR6R-3T3 mouse fibroblast cell line was treated with increasing concentrations of R&D Systems Recombinant Human FGF basic/FGF-2 (Catalog # 233-FB; orange line) or recombinant human FGF-2 from another company (blue line) and cell proliferation was assessed. The bioactivity of the R&D Systems FGF-2 protein was approximately 3-fold greater than the leading competitor’s FGF-2 protein.

R&D Systems Recombinant Human Wnt-3a Protein Displays Higher Activity than a Leading Competitor’s Recombinant Wnt-3a. The bioactivity of R&D Systems Recombinant Human Wnt-3a (Catalog # 5036-WN; orange line) or recombinant human Wnt-3a from another company (green line) was assessed by measuring the ability of the proteins to induce alkaline phosphatase production in the MC3T3-E1 mouse preosteoblast cell line. The ED50 of R&D Systems Recombinant Human Wnt-3a was 1.7-fold better than the leading competitor’s Wnt-3a protein, with more than twice the maximum response.

R&D Systems Recombinant Human GDNF Displays Higher Activity than a Leading Competitor’s Recombinant Human GDNF Protein. The bioactivity of R&D Systems Recombinant Human GDNF (Catalog # 212-GD; orange line) or recombinant human GDNF from another company (blue line) was assessed by measuring the ability of the proteins to stimulate the proliferation of SH-SY5Y human neuroblastoma cells, in the presence of Recombinant Human GFR alpha-1 (R&D Systems, Catalog # 714-GR). The activity of the R&D Systems GDNF protein was approximately 9-fold greater than the leading competitor’s GDNF protein.
R&D Systems Proteins Are Rigorously Tested for Lot-to-Lot Consistency

R&D Systems Recombinant Human PD-1 Displays High Lot-to-Lot Consistency. Two independent lots of Recombinant Human PD-1 (R&D Systems, Catalog # 8986-PD) immobilized at 1 ug/mL were tested for their ability to bind to increasing concentrations of Recombinant Human PD-L1/B7-H1 Fc Chimera (R&D Systems, Catalog # 156-B7) in a functional ELISA. The concentration of Recombinant Human PD-L1/B7-H1 Fc Chimera that produces 50% of the optimal binding response is approximately 0.3-1.8 ug/mL. Each trace on the graph represents data obtained from Recombinant Human PD-1 from a different manufacturing run, demonstrating the lot-to-lot consistency of the protein.

Lot-to-Lot Consistency Testing of Recombinant Human SCF/c-kit Ligand. Two independent lots of Recombinant Human SCF/c-kit Ligand (R&D Systems, Catalog # 11010-SC) were tested for their ability to stimulate the proliferation of TF-1 human erythroleukemic cells. The ED50 for this effect is 1-5 ng/mL. Each trace on the graph represents Recombinant Human SCF/c-kit Ligand from a different manufacturing run, demonstrating the lot-to-lot consistency of the protein.

Lot-to-Lot Consistency Testing of Recombinant Human Flt-3 Ligand. Two independent lots of Recombinant Human Flt-3 Ligand (R&D Systems, Catalog # 308-FKE) were tested for their ability to stimulate the proliferation of BaF3 mouse pro-B cells transfected with mouse Flt-3. The ED50 for this effect is 0.2-1 ng/mL. Each trace on the graph represents Recombinant Human Flt-3 Ligand from a different manufacturing run, demonstrating the lot-to-lot consistency of the protein.

Lot-to-Lot Consistency Testing of Recombinant Human FGF basic/FGF2. Two independent lots of Recombinant Human FGF basic (R&D Systems, Catalog # 233-FB) were tested for their ability to stimulate the proliferation of NR6R-3T3 mouse fibroblast cells. The ED50 for this effect is 0.1-0.6 ng/mL. Each trace on the graph represents Recombinant Human FGF basic from a different manufacturing run, demonstrating the lot-to-lot consistency of the protein.
Serum-Free and Animal-Free Cell Culture
Increase the consistency of your cell cultures as you approach translational studies for regenerative medicine and cell therapy programs. Adopting these media will
- Reduce variability in media composition
- Simplify compliance with regulatory guidelines
- Simplify comparability testing for raw material changes
Customer Success Stories
Recombinant Protein Resources
Proteins Beyond the Catalog
Proteins Beyond the Catalog
If you don’t see the recombinant protein that you need listed on our website, contact us. We have tens of thousands of non-catalog proteins that may include different tags or come from different sources than similar proteins listed on our website.

Evaluating CAR Expression on CAR-T Cells Using FluorokinesTM
Evaluating CAR Expression on CAR-T Cells Using FluorokinesTM
One of the current challenges in the field of CAR-T cell therapy is the lack of a simple assay to easily detect and quantify CAR expression following T cell transduction. Read this application note to learn about the advantages of using R&D SystemsTM Fluorokines fluorescent-labeled proteins to directly stain and detect CAR+ cells by flow cytometry.

Current and Emerging Immune Checkpoint Targets eBook
Current and Emerging Immune Checkpoint Targets eBook
Immune checkpoint proteins play a central role in regulating the activities of different immune cell types and represent some of the most promising targets for cancer immunotherapy. This eBook highlights some of the immune checkpoint molecules that are being investigated as immuno-oncology targets, and the products that we offer for studying these molecules.

Proteins for Stem Cell Culture
Proteins for Stem Cell Culture
Optimize your stem cell cultures with R&D Systems™ cytokines and growth factors. Our proteins provide high levels of bioactivity and lot-to-lot consistency so you can be confident that they will promote robust stem cell expansion and differentiation with minimal variability between cultures. From basic research to preclinical applications, we offer research-grade, Animal-Free™, and GMP-grade cytokines to meet all of your experimental needs.

Cytokine Families
Cytokine Families
Explore the Cytokine Family pages on our website to learn more about why specific cytokines are grouped into families including detailed information about their structures, their receptor complexes, the signaling pathways that they activate, and their functions. These pages contain the most up-to-date listings of related products for each cytokine family along with data examples and featured resources.

Proteins for Immune Cell Culture
Proteins for Immune Cell Culture
Achieve robust, reproducible immune cell cultures with R&D Systems™ proteins. Our proteins are rigorously tested to ensure that they will provide superior performance and lot-to-lot consistency, so you can have confidence in their ability to promote optimal immune cell expansion and differentiation with high batch-to-batch consistency. To meet your needs from basic research to clinical applications, we offer research-grade, Animal-free RUO, and Animal-free GMP-grade proteins.
Background Information
R&D Systems: The Most Trusted Source for Recombinant Proteins
Bio-Techne offers more than 5,000 R&D Systems® recombinant proteins for a variety of different research areas including immunology, cancer, development, neuroscience, and stem cells. With over 30 years of experience, R&D Systems’ rigorous in-house testing and quality control specifications ensure that our recombinant proteins will provide industry-leading bioactivity and purity, lot-to-lot consistency, and low endotoxin levels. As more than 95% of the proteins in our catalog are manufactured in-house, we maintain complete control over the quality of our products and the satisfaction of our customers, which is our number one priority.
To guarantee that each protein meets our customers’ high standards, we fully assess and report the specifications of each protein on our datasheets, including the activity, endotoxin level, and purity. The bioactivities of our proteins are assessed using a variety of different assays depending on the protein being tested. These include cell proliferation, chemotaxis, or cytokine secretion assays, enzymatic assays, functional ELISAs, and surface plasmon resonance (SPR). N-terminal sequence analysis is also performed for each recombinant protein to confirm that the protein produced matches the expected sequence, and the bioactivity and physical state of our proteins are monitored over long periods of time. Freeze/thaw cycles are carried out to ensure that the buffer provides for long-term stability. Additionally, we evaluate lot-to-lot consistency so that researchers don’t have to worry about whether or not their experiments will be reproducible over time. Multiple lots with matching specifications are created for all new proteins and each new lot is tested side-by-side with previous lots to ensure that the new lots display the same level of bioactivity and purity as the previous lots. Each new lot is also tested to make sure that it meets our expectations for endotoxin specifications, which is an industry-leading <0.1 EU/µg. Finally, all of our recombinant proteins are specially formulated for the best stability and are lyophilized from a sterile filtered solution. If our documentation fails to address any questions that you may have about our products, our protein scientists and highly trained technical service team at R&D Systems are always available to assist you.
Our catalog includes recombinant proteins for multiple different species, that are either untagged or have a biotin, Fc, or His tag. We also offer an expanding line of Avi-tag biotinylated proteins. Our standard recombinant proteins are available without or with a carrier protein, which is typically bovine serum albumin (BSA) at a concentration of 50 µg BSA per 1 µg of protein. The presence of the carrier protein gives the lyophilized protein greater stability, maximizes recovery upon reconstitution, and allows easy handling and storage. In addition to the wide selection of proteins that are manufactured under standard conditions, our portfolio also includes R&D Systems Animal-Free™ and GMP-grade recombinant proteins, ProDots® proteins, and custom protein development services.

Gene Engineering Services
Realize the potential of gene engineering by partnering with our experts. Engineer any cell type including T cells and iPSC with our non-viral TcBuster™ gene delivery system.
For cell and gene therapy manufacturing, we offer services that include process development for cell engineering, quality control, custom cell vialing, and regulatory support.
Alexa Fluor® is a registered trademark of Molecular Probes, Inc., Eugene, OR.