RSSL provides regulatory compliant testing for cell and gene therapy (CGT) products at every stage from early research through to lot release. We work with developers of viral vectors, CAR-T therapies and advanced immunotherapies to deliver robust, regulatory ready data.
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World-class GMP laboratories with multidisciplinary expertise
Experienced team providing support across biologics, gene therapy vectors and cell-based products
FDA, MHRA and EMA regulatory awareness built into every method
Rapid and accurate analytical testing without compromising your data integrity
We tailor our engagement to your needs - from single assays to full testing programmes
Detection of inserted genetic material or vector-specific sequences
Confirmation of transgene protein expression, where applicable
Detection of lineage or product-specific markers
Potency testing demonstrates that the product performs its intended biological function and elicits the expected therapeutic activity. As a critical quality attribute, potency provides a quantitative measure of biological activity linked to the product's mechanism of action and is essential for lot release, stability assessment and comparability studies.
Potency can be evaluated using a range of analytical approaches including:
Functional bioassays
Cell based assays that directly measure biological activity
Some of these assays include cytotoxicity assays for cell therapy products, target-cell killing kinetics, immune cell activation assays (e.g., T-cell degranulation or co-stimulatory marker upregulation), and proliferation assays to assess mitogenic or antigen-driven expansion capacity.
Beyond this, our additional capabilities include engineered reporter cell lines (e.g., luciferase or GFP-based systems) to quantitatively assess pathway activation, receptor engagement, or transcription factor–driven signalling downstream of the product's mechanism of action.
RT-qPCR
Measuring transgene mRNA expression levels
The key application of this method is a surrogate measure of biological activity and functional protein output via transcript abundance.
Cytokine release profiling
Quantification of secreted signalling molecules (IFN-γ, TNF-α, IL-2) via ELISA
We use this method to provide a functional readout of immune cell activation and effector function upon target engagement.
Western blot analysis
Protein expression at expected molecular weight
Immunoblotting to confirm expression of the protein of interest, supporting the absence of truncated or aberrant forms.
From single assays to full testing programmes, we'll work with you to build a partnership that meets your scientific and regulatory needs. Contact us to start the conversation.
Our testing is designed to generate data suitable for submissions to the FDA, EMA and MHRA. Methods are developed with current pharmacopeial and regulatory guidance in mind.
We support testing across viral vectors, CAR-T and other engineered cell therapies, gene-modified cell products and broader immunotherapies.
From early-phase characterisation and method development through to validated lot-release testing and stability programmes.
