1:15 PM - 1:30 PM
▲ [18p-E202-2] Towards Immediate Assessment of Immunotherapy Efficacy using Single Cell Level Granzyme B Profiling
Keywords:microfluidics, single cell analysis, granzyme b
Granzyme B (GrB) can serve as an early biomarker to tumors responding to immunotherapy as elevated concentrations or unique expression changes can be found in cancer patients. By measuring GrB activity, responders and non-responders to treatment can be identified that allows physicians to plan out a better therapeutic strategy and limit therapy side effects. To accomplish this, we developed a microfluidic platform that is capable of single cell compartmentalization and on-demand media exchange. The platform was applied to model cells and PBMC samples (healthy donor and anti-PD-1 antibody-treated lung cancer patients) to generate a GrB activity profile.
Photolithography and soft lithography techniques were used in the fabrication of the two-layered PDMS microfluidic device. Pneumatic valves were integrated in the microchip to achieve single cell compartmentalization and rapid fluid exchange. The GrB activity from each cell was detected and measured fluorometrically with the cleavage of a peptide substrate containing GrB recognition sequence (Ac-IEPD-AFC) and AFC label. Cell surface marker staining was performed on PBMC samples to distinguish specific cell populations producing GrB. Results show the capability of the device to conduct single level measurements on real blood samples with higher GrB activity seen in PD-1 antibody treated patient’s PBMC. The study of single cell expression of granzymes is seen important in the medical field as a promising tool in evaluating immunotherapy response.
Photolithography and soft lithography techniques were used in the fabrication of the two-layered PDMS microfluidic device. Pneumatic valves were integrated in the microchip to achieve single cell compartmentalization and rapid fluid exchange. The GrB activity from each cell was detected and measured fluorometrically with the cleavage of a peptide substrate containing GrB recognition sequence (Ac-IEPD-AFC) and AFC label. Cell surface marker staining was performed on PBMC samples to distinguish specific cell populations producing GrB. Results show the capability of the device to conduct single level measurements on real blood samples with higher GrB activity seen in PD-1 antibody treated patient’s PBMC. The study of single cell expression of granzymes is seen important in the medical field as a promising tool in evaluating immunotherapy response.