Sanguine Connections: Blood Biospecimens 101

August 23, 2024

Welcome to Sanguine Connections, exploring the process, challenges, and nuances of biospecimen procurement for translational studies.

Blood Biospecimens 101: Making the Right Choice for Your Immune Cell Studies

A crucial step in your research is finding the right biospecimens for your study – including samples of high-quality that fit your inclusion and exclusion criteria (diagnosed condition, demographics, medications, etc.). For a research project focusing on immune cells, the choice for the type of cellular material largely depends on the specific goals of your study. When deciding what you need, considerations go beyond cell type requirements, including availability, quantities, and cost.

Some studies focus on particular cell populations such as lymphocytes or rare cell subsets, while other studies require all blood components to examine interactions or sensitive cells like neutrophils. When the latter is the case, the choice of whole blood is obvious. However, in other cases, the choice may be less clear, such as initial screening of whole blood may be sufficient followed by more focused analysis with isolated blood components requiring enriched white blood cells whether from a leukopak or isolated peripheral blood mononuclear cells (PBMCs). Below we break down the pros and cons of several types of blood derived products to help you decide what is best for your studies. As this is general, you can always reach out to one of our research specialists for a chat to discuss the specifics of your project.

Whole blood

Whole blood is generally easily accessible and, depending upon quantities needed, PBMCs can still be isolated. As whole blood has a mixed population of cells, more variability occurs within experiments, but may be necessary for analyzing interactions between blood cell types. Whole blood does not require further processing, thus can be received fresh – a necessity for sensitive cells like neutrophils. A limitation with whole blood is rare cell types are often too dilute for experiments.

Buffy coat

Buffy coat is the fraction of mainly white blood cells that after centrifugation is the intermediate between the red blood cells and the plasma. Buffy coat is easily collected from a whole blood sample making it a relatively cost effective method for enriched leukocytes. Buffy coat, however, is a less pure product than PBMCs and volumes are relatively limited.

PBMC

PBMCs are the white blood cells that do not contain granules in their cytoplasms – the lymphocytes (T, B, and NK cells), monocytes, and dendritic cells. PBMCs provide the most pure cell population for immunological studies – at times a necessity for an assay response. PBMCs do require further processing and can be in more limited quantities although we have overcome this challenge with LeukoLots™. Learn more about LeukoLots below and on our website.

Leukopak

Leukopaks are a higher quantity of enriched leukocytes as the product is collected by the white blood cells being separated by apheresis while the plasma and red blood cells are returned to the donor – allowing for significantly more concentrated leukocytes to be collected from a single donor. The quantity of white blood cells collected from a leukopak versus a single blood draw is approximately 30-fold higher. This higher yield provides a product for rare cell types and large scale studies, and is a necessity for therapy development and manufacturing. One limitation can be the need for additional processing to PBMCs. Leukopaks can be costly and depending upon planned usage, require further processing for aliquoting and appropriate freezing to maintain viability and functionality. Several of these limitations have been overcome with LeukoLots.

LeukoLot™

LeukoLots are isolated PBMCs from a leukopak that are aliquoted and cryopreserved. As discussed above, a limitation for PBMCs isolated from a whole blood sample is quantity. These PBMCs are isolated from a leukopak, enabling one to have billions of PBMCs from a single donor collection. Further, as in many use cases, the entirety of the leukopak is not needed at one time, the aliquots allow it to be used over time or shared within your research group or organization with ease.

Choosing the right biospecimens is a pivotal decision in ensuring the success of your research project. Each type of blood-derived product – whole blood, buffy coat, PBMCs, leukopak, and LeukoLot – has its unique advantages and limitations that can significantly impact your study’s outcomes. Whole blood provides a comprehensive snapshot of all blood components, ideal for examining complex interactions but may lack the concentration of rare cell types. The buffy coat offers a cost-effective option for enriched white blood cells but requires additional processing to achieve higher purity. PBMCs, while requiring more sophisticated isolation techniques, offer a more focused and pure population of immune cells crucial for detailed immunological studies. Leukopaks provide a high yield of leukocytes, suitable for large-scale studies and therapy development, although they come with higher costs and processing needs. LeukoLots address many of these challenges by offering aliquoted, cryopreserved PBMCs from leukopaks, balancing high quantity with convenience and flexibility, but at a price similar to a leukopak.

Ultimately, your choice will depend on the specific goals and constraints of your study, including the need for cell purity, quantity, and cost considerations. For detailed guidance tailored to your research needs, don’t hesitate to reach out for a discussion. Understanding these options will help you select the most appropriate biospecimens, ensuring the reliability and success of your research.