Identity
Establishes the tissue origin, cellular characteristics and immunophenotypic profile of the preparation.
CELLMEX Scientific Library
MSC Characterisation
MSC characterisation is the structured scientific process used to establish the identity, composition, viability, purity, safety, stability and functional activity of a mesenchymal stromal cell preparation.
Scientific Definition
What exactly is MSC characterisation?
Mesenchymal stromal cells are heterogeneous, culture-expanded cellular populations obtained from tissues such as bone marrow, adipose tissue and perinatal tissues.
MSC characterisation is the collection of laboratory tests used to determine what the cells are, whether the preparation is sufficiently consistent, and whether it meets predefined research or clinical-quality specifications.
Characterisation does not rely on one marker or one assay. A scientifically credible assessment combines cellular identity, phenotype, viability, purity, microbiological quality, stability and functional information.
Quality
Evaluates viable-cell dose, purity, microbiological safety, stability and consistency.
Function
Examines whether the cells demonstrate a measurable biological activity relevant to their proposed mechanism or intended use.
Minimum Identity Framework
Established criteria for culture-expanded MSCs
The widely used ISCT framework identifies three minimum characteristics for human culture-expanded mesenchymal stromal cell populations.
Plastic Adherence
The cells should demonstrate adherence to tissue-culture plastic when maintained under standard culture conditions.
Adherence is useful for establishing a conventional MSC culture, but it is not unique to MSCs and does not independently prove therapeutic function.
Immunophenotype
Flow cytometry is commonly used to assess the proportion of cells expressing or lacking selected surface markers.
- Positive: CD73, CD90 and CD105
- Negative or low: CD45 and CD34
- Negative or low: CD14 or CD11b
- Negative or low: CD79α or CD19
- Negative or low: HLA-DR
In-Vitro Differentiation
Under defined laboratory conditions, the population should demonstrate differentiation toward:
- Osteogenic lineage
- Adipogenic lineage
- Chondrogenic lineage
These assays demonstrate laboratory differentiation capacity; they do not prove that administered cells will form new tissue in a patient.
Extended Characterisation
Minimum identity criteria are only the beginning
Clinical and advanced research preparations generally require broader testing than the original minimum MSC definition.
Tissue Source
Document whether the cells originate from bone marrow, adipose tissue, umbilical-cord tissue or another defined source.
Donor Qualification
Record donor eligibility, relevant medical information, tissue collection and source-material traceability.
Cellular Morphology
Examine cell shape, attachment pattern, confluence, abnormal morphology and changes during expansion.
Growth Characteristics
Evaluate population-doubling time, expansion capacity, passage history and evidence of reduced proliferative performance.
Senescence
Assess passage-associated cellular ageing and functional decline using appropriate markers or assays.
Genetic Stability
Where scientifically justified, evaluate chromosomal or genomic stability during extended expansion.
Cellular Purity
Determine whether unwanted haematopoietic, endothelial or other cellular populations remain in the final preparation.
Secretory Profile
Characterise selected cytokines, chemokines, growth factors or extracellular-vesicle-associated outputs when relevant.
Cryopreservation Recovery
Compare pre-freeze and post-thaw viability, recovery, phenotype and functional performance.
Laboratory Workflow
A structured MSC characterisation process
Confirm Source and Traceability
Establish tissue origin, donor information, collection, transport and chain of custody.
Review Culture History
Document media, supplements, culture surface, oxygen conditions, passage number and expansion time.
Examine Morphology and Growth
Evaluate attachment, cellular appearance, confluence, proliferation and abnormalities.
Perform Immunophenotyping
Use a defined flow-cytometry panel with appropriate controls, thresholds and reporting.
Evaluate Differentiation
Confirm expected in-vitro lineage-associated differentiation under controlled conditions.
Assess Safety and Purity
Review microbiological testing, unwanted populations, process residuals and cellular aggregates.
Measure Functional Activity
Apply mechanism-relevant assays appropriate to the intended research or clinical application.
Compare with Release Specifications
Determine whether the final batch meets predefined identity, quality, safety and functional acceptance criteria.
Quality Control
Characterisation for clinical-quality preparations
A product intended for administration requires additional release and safety considerations beyond basic MSC identity.
Viable-Cell Dose
Determine total cell number, viable-cell concentration, recovery and the acceptable viability threshold.
Sterility-Related Testing
Evaluate microbial contamination using methods appropriate to the process, sample and release timeline.
Mycoplasma
Assess mycoplasma contamination through validated or otherwise appropriately qualified testing.
Endotoxin
Measure bacterial endotoxin where relevant to the final product and intended route of administration.
Aggregation and Particulates
Evaluate clumping, visible particles and other characteristics that may affect administration or patient safety.
Stability and Holding Time
Establish how transport, temperature, storage and time before administration affect product quality.
Functional Characterisation
Potency should relate to the proposed mechanism
Surface phenotype confirms selected characteristics, but it does not demonstrate that an MSC preparation has the biological activity required for a particular application.
Immunomodulatory Activity
Assays may evaluate effects on lymphocyte proliferation, macrophage responses, inflammatory signalling or other immune-cell functions.
Angiogenic Activity
Testing may examine endothelial-cell migration, network formation, survival or vascular-associated signalling.
Cytoprotective Activity
Assays may evaluate whether MSC-derived signals influence recipient-cell survival under defined stress conditions.
Matrix-Related Activity
Functional testing may address matrix production, degradation, fibrosis-associated signalling or tissue-remodelling mechanisms.
Secretome or EV Activity
When the proposed mechanism involves released factors, relevant secretory or extracellular-vesicle-associated activity may be assessed.
Assay Matrix
Complex cellular products may require several complementary assays rather than one universal potency test.
Clinical Relevance
How characterisation supports medical use
Characterisation helps physicians and investigators understand the exact cellular preparation being considered and whether it meets applicable protocol and quality requirements.
Clinical-Trial Products
Characterisation supports product definition, batch release, comparability, safety monitoring and interpretation of clinical results.
Protocol-Based Clinical Programmes
Where legally permitted, defined product specifications should be linked to the clinical protocol, patient evaluation and administration plan.
Manufacturing Comparability
Testing helps determine whether changes to media, equipment, passage, scale, cryopreservation or formulation alter the product.
Treatment Selection
Product data allow the treating physician to distinguish one MSC preparation from another instead of relying on the general term “stem cells.”
Safety Investigation
Batch records and analytical results support the investigation of unexpected reactions, quality deviations or adverse events.
Research Interpretation
Detailed product characterisation helps determine whether clinical outcomes can reasonably be compared across studies.
Uses and Indications
Characterisation does not establish an indication
MSC characterisation is applicable wherever an MSC preparation is being developed, manufactured, studied or evaluated. It is not itself a medical treatment and does not create a clinical indication.
Characterised MSC products are being investigated across musculoskeletal, immune-mediated, neurological, vascular, wound-healing and organ-injury research programmes.
Evidence from one indication or one MSC product cannot automatically be applied to a different tissue source, manufacturing process, dose, route or disease.
Clinical and regulatory qualification
Meeting the original MSC minimum criteria does not by itself establish sterility, purity, genetic stability, potency, manufacturing consistency or suitability for administration.
MSC products from different tissues, donors, laboratories or manufacturing processes cannot be assumed to be equivalent.
Surface-marker expression and in-vitro differentiation do not independently demonstrate that cells will regenerate cartilage, neurons, organs or other complex tissues in patients.
Clinical use must be considered in relation to the specific product, patient, indication, evidence, manufacturing standards and applicable regulatory requirements.
Availability of an MSC preparation at a treatment facility does not by itself establish regulatory authorisation or demonstrated clinical effectiveness.
The CELLMEX Approach
Characterisation across the product lifecycle
Source Definition
Record tissue origin, donor, collection, traceability and starting-material quality.
Process Control
Define isolation, culture, passage, cryopreservation, recovery and final formulation.
Integrated Analytics
Interpret morphology, immunophenotype, viability, purity, microbiology and stability together.
Mechanism-Relevant Function
Connect functional assays to the proposed biological mechanism and intended clinical programme.
Selected Scientific References
MSC identity, potency and clinical-quality evaluation
Dominici M, et al. Minimal criteria for defining multipotent mesenchymal stromal cells.
Cytotherapy. 2006;8(4):315–317.
View publicationViswanathan S, et al. Mesenchymal stem versus stromal cells: ISCT position statement on MSC nomenclature.
Cytotherapy. 2019;21(10):1019–1024.
View publicationGalipeau J, et al. ISCT perspective on immune functional assays for MSC potency release.
Cytotherapy. 2016;18(2):151–159.
View publicationGalipeau J, Sensébé L. Mesenchymal stromal cells: clinical challenges and therapeutic opportunities.
Cell Stem Cell. 2018;22(6):824–833.
View publicationEuropean Medicines Agency. Reflection paper on stem-cell-based medicinal products.
Quality, nonclinical and clinical considerations for defined stem-cell-based medicinal products.
View EMA documentU.S. Food and Drug Administration. Patient and consumer information about regenerative-medicine therapies.
Regulatory and patient-safety information concerning marketed regenerative-medicine products.
View FDA information
Scientific Information
Request information concerning CELLMEX MSC characterisation
Physicians, researchers and institutions may request information concerning cellular identity, immunophenotyping, quality control, potency assessment and research collaboration.