Leukopak datasheets across the industry tend to blur two different things: specifications that are released against, and typical values that describe what usually arrives. For whole leukopak formats the distinction matters more than it looks, because a number quoted as a specification when it is really a typical value will eventually fail an incoming inspection that was written against it.
What is specified for whole leukopak formats
A single-donor leukopak unit provides a minimum of ten billion cells. Units are available fresh or cryopreserved, in whole, half, quarter and documented custom formats. Cryopreserved material is held in vapor-phase liquid nitrogen. Both research and cGMP formats exist.
There is no published viability or purity threshold for whole leukopak formats. That is worth stating plainly rather than leaving a reader to assume one exists. A whole leukopak is an apheresis product, not an isolated cell population, and the meaningful quality measures for it are different from those used for a purified subset.
Isolated products do carry thresholds, and they differ by product
| Product | Published specification |
|---|---|
| Cord blood derived CD56 positive NK cells | One million or two and a half million cells per vial; viability 90 percent or above; CD56 positive purity 90 percent or above; immunomagnetic selection |
| Peripheral blood derived NK cells | Five million or ten million cells per vial; post-thaw viability 85 percent or above |
| Disease-state donor material | Post-thaw viability above 80 percent; research use only |
| Whole leukopak, fresh or cryopreserved | Minimum ten billion cells per single-donor unit; no published viability or purity threshold |
The pattern is that isolated, selected populations carry purity and viability numbers because selection makes those measurable and meaningful, while a whole apheresis product is specified on cell content and donor characterization instead. Mixing the two sets of expectations is the most common source of specification disputes.
Related product
Leukopak formats. Whole, half, quarter and custom single-donor units, fresh or cryopreserved.
Fresh and cryopreserved are different operational commitments
Fresh material has to be used on a schedule set by the collection, which means the receiving laboratory has to be ready on the day. Cryopreserved material decouples collection from experiment and allows the same lot to be used across a series of runs, which is usually the more important property for a program running comparisons over months.
The trade is that cryopreservation and thaw introduce their own variability, and some readouts tolerate that better than others. Signalling and phenotyping generally survive well when the thaw is consistent. Functional assays involving fragile populations are more sensitive, and granulocyte-dependent readouts are not served by either format once density gradient separation has been applied.
Custom formats exist, and specifying them early is cheaper
Whole, half and quarter units cover most requirements, and documented custom formats are available where a process needs a specific cell number or volume per unit. Specifying that at the outset is materially easier than subdividing a whole unit in the receiving laboratory, which introduces an extra open step and an extra freeze-thaw for anything not used immediately.
Where a study will run over an extended period, requesting the material as multiple smaller units from the same donor collection preserves lot consistency across the whole series without repeated subdivision.
Donor characterization is the other half of the specification
Because whole leukopak quality is not expressed as a purity number, donor characterization carries proportionally more of the information. High-resolution NGS HLA genotyping is performed across HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DQ and HLA-DP, KIR genotyping is included, and donors undergo a fourteen-marker infectious disease screening panel.
Donor selection can be scoped by HLA genotype, age, sex, ethnicity, blood type, CMV and EBV status, BMI, smoking status and disease state, all subject to availability. The donor network numbers more than fifty thousand donors, and eligible donors can be scheduled for repeat collection, which is what makes lot-to-lot continuity from a single donor identity possible.
Related material: leukopak formats and specifications, cryopreserved PBMCs, and what a mononuclear cell preparation contains.
Frequently asked questions
Is there a published viability specification for whole leukopaks?
No. Whole leukopak formats carry a minimum of ten billion cells per single-donor unit, and there is no published viability or purity threshold. A whole leukopak is an apheresis product rather than an isolated population, so it is specified on cell content and donor characterization.
Why do isolated products carry purity numbers when leukopaks do not?
Because selection makes purity measurable and meaningful for a defined population. Cord blood NK cells, for example, are listed at 90 percent or above CD56 positive purity. A whole apheresis product has no equivalent target population to express purity against.
When is fresh material worth the scheduling burden?
When the readout is sensitive to cryopreservation and thaw, particularly functional assays on fragile populations. For programs running comparisons over months, cryopreserved material from one lot usually gives better consistency.
Should a whole unit be subdivided in the receiving laboratory?
Preferably not. Requesting half, quarter or a documented custom format avoids an extra open step and an extra freeze-thaw for the unused portion. Multiple smaller units from one collection also preserve lot consistency across a long study.
How is cryopreserved material stored?
In vapor-phase liquid nitrogen. Both research and cGMP formats are available, with cGMP requiring a clinical master services agreement and Quality Assurance release rather than technical release.
What donor information comes with a leukopak?
High-resolution NGS HLA genotyping across HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DQ and HLA-DP, KIR genotyping, and a fourteen-marker infectious disease screening panel. Selection can be scoped by genotype and by donor characteristics, subject to availability.
What viability specification applies to this material?
Disease-state donor material carries a post-thaw viability specification above 80 percent. That figure applies to the disease-state line specifically and is not carried across from healthy donor products.
Can this material be used for clinical manufacturing?
No. Disease-state donor material is supplied for research use covering discovery, drug screening and biomarker work. Material intended for further manufacturing is a separate cGMP scope with its own agreement and documentation requirements.
Talk to OrganaBio
Need this material for a specific process?
Formats, vial sizes and donor characterization vary by product, and custom formats are documented where a process needs them. Tell us what your process requires and the scientific team will confirm what can be supplied.
