By PD Dr. Arno Kromminga and Dr. Juliane Ober-Blöbaum
While viral vector-based gene therapies have high DNA transferring efficiency, innate immunity and antigen-specific adaptive immune responses against vector-derived antigens can reduce the efficacy and stability of in vivo gene transfer. ELISpot is a method that is commonly used to detect and monitor cellular immune responses to specific antigens. However, unlike ADA- or NAb-detecting protocols used to measure humoral responses, there is currently no regulatory guidance on how to develop and validate ELISpot assays for gene therapy development.
On 2 September, myself and my colleague, Dr. Juliane Ober-Blöbaum, Principal Investigator at BioAgilytix, will host a live webinar to take a closer look at how the industry is working to harmonize best practices for the development and validation of ELISpot methods, and to set appropriate assay expectations and performance criteria for monitoring cellular immunity. Specifically, we will discuss:
What the 2019 WRIB Recommendations Say
Last year’s annual WRIB conference dedicated an entire full-day session to gene therapy bioanalytical challenges. One of the ‘hot topics’ included ELISpot as an approach to gene therapy bioanalysis. ELISpot assays require a complex workflow from sample collection to testing, and therefore assay variability issues can arise from many potential sources. We will examine the recommendations in the 2019 WRIB white paper generated from this discussion, which emphasize the need to standardize approaches for sample logistics and processing including peripheral blood mononuclear cells (PBMC) preparations.
Current Challenges with ELISpot in Support of Gene Therapy Development
A key challenge leading to ELISpot assay variability is a lack of high-quality PBMCs as positive samples. We will discuss why varied preparation protocols can impact the quality of the blood and how using cryopreserved PBMCs can optimize performance in functional ELISpot assays.
The determination of the optimal concentration of each peptide pool is also critical step in ELISpot method development, as unspecific responses from overdosing or stimulating other additives in the formula need to be avoided. We will step through a case study where the lowest possible peptide pool was established, resulting in a consistent mean spot count in all donors.
A Discussion on Evolving Trends
To conclude our webinar, Dr. Ober-Blöbaum and I will review the evolving trends in ELISpot method development and validation in support of gene therapies, talking together and with our audience about items such as:
- Is it optimal to run ELISpot assays in duplicate or triplicate?
- Is one (e.g., interferon gamma) read-out sufficient to assess T-cell response
- What are the regulatory parameters to be considered with ELISpot?
Join the Webinar to Learn More
Wednesday, 2 September at 10:00 AM EDT / 15:00 BST
Are you developing a viral vector-based gene therapy? Are you interested in hearing the latest thinking regarding development and validation of ELISpot assays for cellular immunity monitoring for gene therapies? Then you won’t want to miss this webinar! Register here to reserve your spot.