Primary cells from STEMCELL can help you reach your research goals: choose from ready-to-use fresh or cryopreserved cells including mononuclear cells (MNCs), purified immune cells, or stem cells isolated from blood or bone marrow*. Cells purchased from STEMCELL are shipped with a Certificate of Analysis, indicating guaranteed Quality Control testing of cell count, viability, and purity.

Take advantage of STEMCELL's custom primary cell services: from flexible delivery and sourcing of custom products, to characterization and assaying, STEMCELL is here to help.

*Due to government regulations, cord blood and bone marrow products may not be available in your region. Please contact your local Sales representative or Product and Scientific Support (techsupport@stemcell.com) for further information.

STEMCELL offers a selection of human primary cells including:

Cryopreserved Peripheral Blood Products*:

• PBMCs isolated from normal donors: High-resolution HLA typing and CMV status available
• CD34+ cells, B cells, T cells, NK cells, DCs, monocytes, and other cell subsets available
• PBMCs isolated from diseased state donors: Crohn’s Disease, Lupus, Psoriasis, and more

• CD34+ cells from single or mixed donors
• MNCs, T cells, B cells, NK cells, monocytes, and other cell subsets available

• Whole blood: Collected in ACDA, CP2D, EDTA, or Na Heparin
• Leukopaks: Full, half, quarter, and tenth packs available

*For a full listing of STEMCELL's human primary cell offerings, including bone marrow products** please visit our primary cell product page.

**Due to government regulations, cord blood and bone marrow products may not be available in your region. Please contact your local Sales representative or Product and Scientific Support (techsupport@stemcell.com) for further information.

STEMCELL can help you with your experiments by offering a suite of products and services designed to help you get the results you need. Overcome challenges in your experimental procedures by combining the power of STEMCELL media and reagents with the knowledge of our scientists and educators through Contract Assay Services (CAS) or our training programs.

CAS is a contract resource organization (CRO) established within STEMCELL that specializes in primary cell-based assays. CAS offers services including the Colony-Forming Unit (CFU) assay for for hematotoxicity testing as well as the development of custom assays for a variety of cell types.

Find out more about CAS >

If you would prefer to learn about the techniques and use them in-house, STEMCELL's training programs offer comprehensive, theoretical, and hands-on training--customizable for your specific needs.

Find out more about STEMCELL's training programs >

STEMCELL recommends that you use primary cells for your experiments where possible. Human primary cells are increasingly recognised as the better choice for your experiment as the data obtained from in vitro assays or in vivo models using these cells have increased physiological relevance. Primary cells are isolated directly from tissues--including blood and bone marrow--and are therefore more representative of the tissue being investigated than cell lines.

Read more about the relevance of primary cells versus cell lines for your experiment in this article >

Primary cells may be used for research into downstream applications such as disease modelling, genome editing, drug discovery, and more.

STEMCELL's primary cell products are provided for laboratory research use only: they are not suitable for diagnostic or therapeutic use, and are not to be administered to humans. Primary cell products shall be used in accordance with all applicable laws, rules and regulations, including but not limited to applicable privacy laws, and in accordance with any Product Information Sheet or any other label or document shipped with or otherwise associated with any of the products. STEMCELL cannot guarantee the biological function or any other properties associated with performance of cells in a researcher’s individual assay or culture systems.

To determine the concentration of cells in a suspension, you must take both the number of cells and the dilution of the suspension into account. For tips and tricks on this process, explore our templates and resources which have been designed to help you accurately count cells and measure cell viability.

Access Now >

Determining the concentration of cells in a suspension is a vital part of many workflows: most life-science research, including research into cell therapy, drug development, and stem cell biology requires knowledge of cell concentrations and viability for comparison and analysis.

WBCs are separated from the plasma via the apheresis machine, which uses a variety of methods, including density gradient separation, to separate out the various fractions of the blood.

The Certificate of Analysis (CoA) for frozen leukopaks manufactured after May 2022 now includes flow cytometry plots showing the percentage of monocytes (CD14+), B cells (CD19+), T cells (CD3+, CD4+, CD8+), and NK cells (CD56+CD3-). Flow cytometry plots for purified/isolated cell types that have a purity specification noted on the CoA can typically be provided upon request at: https://www.stemcell.com/coa#request-certificate-tab

Additionally, you can also reach out to your sales representatives or the Product and Scientific Support team (techsupport@stemcell.com) for more information. Only markers included in the purity specification will be shown on the flow plots.

Some products, such as fresh PBMCs and leukopaks, do not have purity specifications listed on the CoA. For these products, we do not perform any flow cytometry analysis during standard manufacturing and cannot provide flow cytometry plots retroactively. However, if flow cytometry plots and purity analysis are desired for PBMC lots, or if additional markers that are not routinely included for purity analysis of isolated cell types are of interest, they may be proactively requested for an additional fee. Please reach out to your sales representative to discuss further.

You can specify your preference for the following characteristics when ordering cells:

• Age
• Gender
• Ethnicity
• Weight
• Height
• Smoking Status
• HLA type

Information about other donor characteristics may be requested, e.g. CMV status, EBV status, vaccination status, and others. Contact us for more information.

STEMCELL collects donor demographic information ethically, using consent forms and protocols approved by either an Institutional Review Board (IRB), the Food and Drug Administration (FDA), the U.S. Department of Health and Human Services, and/or an equivalent regulatory authority. Donations are performed in the United States in compliance with applicable federal, state, and local laws, regulations, and guidance.

Our Quality Assurance, Quality Control, and Regulatory Affairs departments are ready to assist you with any necessary documentation to meet specific institutional requirements, including supplier approval for ease of procurement.

Contact us for further information on the collection of donor demographics.

STEMCELL obtains primary cell products ethically: donations are performed in the United States in compliance with applicable federal, state, and local laws, regulations, and guidance. Cells are obtained from donors who are voluntarily participating in a donor program approved by an IRB, FDA, or equivalent regulatory authority and have either donated their cells or have been reasonably compensated for their time and effort during their donation, in accordance with FDA regulations or as approved by an IRB. Donors are aware that the cells may be used for research applications and have waived any rights generated from the research applications. Donors are protected by strict controls on personal identifiers and researchers cannot access any identifying information about donors.

Donors are pre-screened for general health and viral status, including HIV-1, HIV-2, Hepatitis B, and Hepatitis C (see Donor Viral Screening Policy for more information). All products should be handled at Biosafety Level 2 (BSL-2) or higher, and universal handling precautions for biological samples should be used. Additional screening or analysis is available upon request. Customers purchasing primary cell products from STEMCELL acknowledge that they are required to treat all products as potential biohazard materials and waive STEMCELL of any liabilities from contaminations of infectious pathogens in these products.

Contact us for further information on the collection of human primary cells by STEMCELL.

STEMCELL's donor viral screening policy for human primary cells is outlined below:

Leukopak, Whole Blood, and Bone Marrow - Fresh Products:
Donors are screened for HIV-1, HIV-2, Hepatitis B, and Hepatitis C. If the donor has tested negative within 90 days prior to donation, the product will be shipped with negative test results. If the donor has not been screened within 90 days prior to collection, a test sample will be taken at the time of collection and the product will be shipped before the screening results are available. In the event that a test result is positive, the customer will be contacted as soon as possible (usually within 24 - 72 hours of the time of shipment).

LRS Cone - Fresh Products:
Donors are screened for HIV-1, HIV-2, Hepatitis B, and Hepatitis C. If the donor has tested negative within 90 days prior to donation, the product will be shipped with negative test results. If the donor has not been screened within 90 days prior to collection, a test sample will be taken at the time of collection and the product will be shipped before the screening results are available. In the event that a test result is positive, the customer will be contacted as soon as possible (usually within 4-7 business days from the time of shipment).

Leukopak Products, Whole Blood, and Bone Marrow - Cryopreserved Products*:
Donors are screened for HIV-1, HIV-2, Hepatitis B, and Hepatitis C. If the donor has tested negative within 90 days prior to donation, the product will be shipped with negative test results.

Cord Blood Products - Cryopreserved Products:
Testing for HIV-1, HIV-2, Hepatitis B, and Hepatitis C is performed on a sample of maternal blood and/ or donated cord blood. Products are shipped with negative test results from the donor screening.

*Due to government regulations, cord blood and bone marrow products may not be available in your region. Please contact your local Sales representative or Product and Scientific Support (techsupport@stemcell.com) for further information.

Donors can be recalled for your experiments, however future donations are at the discretion of the donor and are not guaranteed.

Timelines for donor recall are as follows:

• Leukopaks: recallable 56 days after last donation.
• Whole blood: recallable 56 days after last donation.
• Mobilized peripheral blood leukopak: There is a lifetime limit of 1 mobilized peripheral blood donation per donor. Donors are still eligible for non-mobilized blood or bone marrow collections.

Please contact us for more information.

You may request donors with specific medication requirements. However, it should be noted that this may affect lead time and can require a custom quote to be generated in some situations.

Contact us for more information.

HLA type can be requested for most primary cell products. Please be advised that the request for HLA data incurs an additional fee.

Contact us for more information.

Yes, over time we do see decreased efficiencies from donors who have been recalled frequently over long periods of time.

The United States Food and Drug Administration (FDA) does not recommend using laboratory tests to screen asymptomatic blood donors at this time. Therefore, donor centers that are collecting blood are not required to test donors for active disease. However, standard screening processes that are already in place require donors to be healthy and feel well on the day of donation. Blood donations are not collected from anyone with symptoms of COVID-19, including fever, cough, and shortness of breath. As routine screening cannot completely guarantee that a donor is virus-free, STEMCELL continues to recommend that all primary cell products be treated as potentially infectious and are only used following appropriate handling precautions such as those described in biological safety level 2.

For customers who are interested, COVID-19 testing for donors is available and can be performed for an additional fee. Please contact your local Sales Representative or Product and Scientific Support (techsupport@stemcell.com) for further information.

According to the United States Food and Drug Administration (FDA), respiratory viruses are generally not known to be transmitted by implantation, transplantation, infusion, or transfer of human cells, tissues, or cellular or tissue-based products (HCT/Ps). While the potential for transmission of COVID-19 via HCT/Ps is unknown at this time, there have been no reported cases. Similarly, there have been no reported cases of any coronavirus transmission, including SARS and MERS, by blood. STEMCELL continues to recommend that all primary cell products be treated as potentially infectious and are only used following appropriate handling precautions such as those described in biological safety level 2.

Yes. A limited supply of primary cell products manufactured prior to November 2019 is still available. Please contact your local Sales Representative or Product and Scientific Support (techsupport@stemcell.com) for further information.

Frozen PBMCs, frozen plasma, fresh whole blood (available in select territories only), and other custom products from COVID-19-recovered donors, who have provided proof of positive COVID-19 test results, are offered but are subject to donor availability. A donor is considered COVID-19-recovered after 28 days from their last fever. Please contact your local Sales Representative or Product and Scientific Support (techsupport@stemcell.com) for further information.

Find additional information about COVID-19 here:

• U.S. Food & Drug Administration
• • Updated Information for Blood Establishments Regarding the Novel Coronavirus (COVID-19) Outbreak
• AABB’s Coronavirus Resources
• • Report: Impact of 2019 Novel Coronavirus and Blood Safety
• World Health Organization
• • Report: Maintaining a safe and adequate blood supply during the pandemic outbreak of coronavirus disease (COVID-19)

Custom primary cell products include:

• Rare or difficult-to-isolate cell types
• Specific donor recruitment criteria
• Collection in alternative anticoagulants
• Collection in alternative formats, e.g. bags, vial sizes, total cell counts, etc.
• Donor-matched collections for fresh and/or cryopreserved cells

Contact us for more information.

The cell count will vary depending on the donor, and we cannot guarantee the number of cells you will be able to isolate after processing the sample. However, STEMCELL Technologies’ minimum cell counts for product release at the time of shipping are:

• Full size leukopak: 9 x 10e9
• Half-size leukopak: 5 x 10e9
• Quarter-size leukopak: 2.5 x 10e9
• Tenth-size leukopak: 0.9 x 10e9

*These minimum cell counts are the acceptance criteria for product release at the time of shipping. The sizes are the same for frozen leukopaks, however, for frozen leukopaks we count the cells at the time of freeze. Viability of these cells as well as the fresh cells after wash is typically above 90%.

Cord blood can be HLA typed upon request. Please contact your local Sales Representative or the Product & Scientific Support team at techsupport@stemcell.com for more information, or complete our contact us form and we'll get back to you.

We do not currently offer GMP-certified cells. However, as part of our Key Relationships Management (KRM) Program, STEMCELL may be able to support the use of our products as ancillary materials under an approved Investigational New Drug application (IND), Clinical Trial Authorization/Application (CTA), Biologics License Application (BLA), or equivalent regulatory filing. STEMCELL has supported over 35 clinical trials worldwide using our products as ancillary materials.

See Regulatory Support for more information.

It is not recommended to re-freeze aliquots of primary human cells that have been previously cryopreserved, before or after cell expansion. Unlike cell lines, primary cells have a limited life span and are more sensitive to the freezing and thawing procedure.

The best culture medium will depend on the type of primary cell you are working with. STEMCELL offers a range of cell culture media and reagents, optimized and standardized for specific cell types. Refer to the Product Information Sheet (PIS) or contact Product and Scientific Support at techsupport@stemcell.com for more information about the best media for your cell type.

No, RosetteSep™ is optimized and intended for use in fresh whole blood. Please refer to your isolation product's Information Sheet for additional information.

STEMCELL offers a broad range of diseased cryopreserved PBMCs. Examples of disease types include Rheumatoid Arthritis, Ulcerative Colitis, Crohn's Disease, COPD, Lupus, Osteoarthritis, Celiac Disease, Asthma, Psoriasis, Diabetes Type I, and Diabetes Type II.

Please contact us for more information about available diseased cells.

Leukopaks are red due to residual red blood cells (RBCs) in the sample; however, they do not affect the cell quality. Non-red leukopaks are not available as the degree of redness is often impacted by donor-to-donor variability. For a usual leukopak, a 3:1 ratio of RBCs to WBCs is observed. Compared to that of whole blood (700:1), leukopaks are a highly enriched source of WBCs and there are minimal RBCs in the bag.

Both fresh and frozen leukopaks are ideal starting materials for downstream cell isolation when large numbers of cells are required, reducing the time and reagents needed to process cells of interest. However, frozen leukopaks provide additional convenience by allowing you to start experiments as per your schedule. Additionally, cell viability may be better preserved in frozen leukopaks during global shipping. Frozen leukopaks can also provide you with access to samples from the same lot at a future date.

It is recommended to use the fresh leukopak immediately upon arrival and not to store it at room temperature. If storage upon arrival is needed for longer periods of time, storing the leukopak at 4°C has been shown to be acceptable depending on your cell type of interest.

It is recommended to use cold ammonium chloride for processing leukopaks.

STEMCELL offers multiple automation options such as the RoboSep™-16 and the RoboSep™-C for fully automated cell isolation from both fresh and frozen leukopaks.

If washed with DNAse- and FBS-containing media, there is minimal risk of cell clumping after the anticoagulant and cryopreservation media are washed off.

Diluting the leukopak 1:1 with PBS + 2% FBS works well for Lymphoprep™ or Ficoll™ processing. In some cases where the leukocyte concentration is high, a 1:2 dilution (e.g. 50 mL sample + 100 mL medium) can help improve separation. Due to the concentrated nature of leukopaks, the cell layer at the interface can be quite thick. Lower dilution will result in a thicker cell layer at the interface and may reduce the efficiency of cell collection.

It is not recommended to thaw and refreeze frozen leukopaks. Mononuclear cells (MNCs) from fresh leukopaks can be subsequently cryopreserved, but it is not recommended to refreeze MNCs from cryopreserved leukopaks. Human primary cells typically do not survive multiple cryopreservation cycles very well; one can expect to see decreased viability and low cell recovery after a second freeze/thaw cycle.

It is possible; however, without the FBS or some other similar additive (BSA, HSA, etc.), there is a risk of cell clumping and increased cell loss since the FBS acts as a "cushion" during the processing.

It is recommended to use CryoStor® CS10 to freeze samples as this is a serum- and animal component-free product that will help your cells handle the freeze-thaw process. While other freezing media may be used, there may be varying degrees of success based on the formulation.

STEMCELL has observed similar functionality in most immune cell types upon thawing of cryopreserved leukopaks. Some more sensitive cells (such as monocytes) may have lower performance than the cells isolated from a fresh leukopak.

Upon cryopreservation, cell viability in the frozen leukopak is greater than 90%. After thawing and the cleanup process, the viability is usually greater than 90%.

It is observed that granulocyte counts are typically rather low for our leukopaks, averaging around 5% of the total number of cells in the leukopak.

For a full, fresh leukopak, the volume does vary between donors and collections, with full collection volumes being between 125 mL and 150 mL.

While this depends on your downstream applications, in general, negative selection offers true untouched cell samples, which is our recommended mode of isolation where applicable. Choose from a wide range of manual or automated immunomagnetic and column-free EasySep™ cell isolation kits to isolate your cell subset of interest.

It is possible to isolate CD34+ HSCs from a leukopak, but there are very few present in a normal (non-mobilized) leukopak. Typically, between 0.03% and 0.09% of leukocytes in the leukopak are HSCs. For this cell type, STEMCELL strongly recommends a starting sample with high HSC counts, such as bone marrow, cord blood, or mobilized leukopaks.

After thawing and cleanup, viability is typically greater than 90% for a frozen leukopak.

While CD34+ cells can be isolated from normal peripheral blood leukopaks, the quantities are often too low to make it worth the isolation. To get an acceptable number of CD34+ stem cells from a leukopak, it is recommended to purchase the pre-isolated CD34+ cells from mobilized leukopaks offered at STEMCELL. CD34+ samples are collected from donors mobilized with either granulocyte colony stimulating factor (G-CSF), plerixafor (PLX), or a combination of the two compounds. These cells are collected under industry best practices and carefully monitored throughout the process to ensure maximal quality of these samples.

STEMCELL can deliver fresh cells within North America.

Contact your local Sales Representative or cellorders@stemcell.com for further information.

STEMCELL can deliver frozen cells in a number of countries: availability will depend on the cell type and government regulations.

Please contact your local Sales Representative or Product and Scientific Support (techsupport@stemcell.com) for further information.

Same-day delivery is available in select regions.

Contact cellorders@stemcell.com or your local Sales Representative for further information.

Fresh blood collection scheduling depends on your donor requirements:

• No donor specifications: collection will be scheduled within 1-2 weeks of the request date.
• Donor specifications: collections will be scheduled within 1-2 weeks of the request date, however it may take longer to locate donors meeting your requirements.

Frozen primary cells are shipped in CryoStor™ CS10 cyropreservation medium (Catalog #07930), with the exception of CD34+ and CD36+ cells (sourced from cord blood, bone marrow, or peripheral blood), which are shipped in StemSpan™ SFEM (Catalog #09600) + 10% DMSO. Frozen cells are shipped on dry ice or, if requested, liquid nitrogen.

Please contact your local Sales Representative or use our contact us form for the most up to date information on primary cell availability in your region.

Fresh leukopak products are shipped by default in a certified refrigerated packaging capable of holding a constant internal temperature range of 2-8°C for a period of up to 48 hours. You also have the option of shipping at ambient temperatures if that is preferable.

For same day deliveries, leukopaks will be shipped at ambient temperatures due to the short transit time between product collection and utilization.

Frozen leukopak products are shipped on dry ice with liquid nitrogen shipping available upon request. For best results, it is recommended to use the leukopak product immediately upon receipt. Otherwise, store at -135ºC or colder.