Evaluating cancer vaccine–induced T-cell functionality with FluoroSpot
Published: August 29, 2025
2 minute read
Authored by: Jens Gertow
Our friends at Elicio Therapeutics recently shared exciting results from one of their cancer vaccine trials. Their KRAS-targeted amphiphile vaccine elicited strong and durable T-cell responses in pancreatic and colorectal cancer. Using FluoroSpot, these responses can be studied in greater depth, revealing the polyfunctional T cells most closely associated with clinical benefit.
Why durable immunotherapy effects matter
KRAS-mutant pancreatic and colorectal cancers remain among the most difficult malignancies to treat, especially in minimal residual disease (MRD) where relapse is common despite standard therapy. In this phase 1 trial, a lymph node-targeted vaccine composed of KRAS peptides plus an adjuvant was designed to amplify immunogenicity right at the source – the lymph nodes.
The results were promising:
- 21 of 25 patients developed mKRAS-specific T-cell responses.
- Patients who crossed a defined T-cell response threshold experienced significantly better and more durable outcomes – including improvements in relapse-free survival (RFS) and overall survival (OS).
Why FluoroSpot matters for immune readouts
Although flow cytometry with intracellular cytokine staining was also applied, FluoroSpot provided unique advantages for monitoring IFN-γ and Granzyme B secretion:
- Sensitivity: A robust, overnight assay that quantifies cytokine-secreting cells immediately upon secretion and throughout the stimulation process is ideal for clinical immune monitoring.
- Functional relevance: By detecting active IFN γ and Granzyme B secretion rather than just expression, FluoroSpot reflect effector potential more meaningfully than assays that rely solely on intracellular markers.
- Prognostic insight: Polyfunctional T-cell subsets are often linked to durable clinical benefit and could be clearly identified by this trial.
Concluding perspective
The AMPLIFY-201 trial underscores the potential of lymph-node-targeted vaccination to induce potent and durable KRAS-specific T-cell responses that translate into meaningful RFS and OS benefits. Adding FluoroSpot to the immune monitoring toolkit provided deeper insight into functional T-cell quality and helped identifying the polyfunctional effector subsets most correlated with long-term remission.
In our view, these results pave the way for more precise biomarker strategies in future cancer vaccine trials.
Mabtech products used in this study