The cytotoxicity % is calculated by the equation below.
Cytotoxicity % = (Live counts of control - Live counts of treated) / Live counts of control * 100
By labeling the target tumor cells with non-toxic, non-radioactive calcein AM or transfect with GFP, we can monitor the killing of the tumor cells by CAR-T cells. While live target cancer cells will be labeled by a green calcein AM or GFP, the dead cells cannot retain the green dye. Hoechst 33342 is used for stain all cells (both T cells and tumor cells), alternatively, target tumor cells can be stained with membrane bound calcein AM, PI is used for stain the dead cells (both T cells and tumor cells). This staining strategy allows for the discriminate of different cells.
The Countstar S2 System combines the two fluorescence channels plus a bright field digital microscope, an image cytometer, and a cell counter in a single bench-top instrument. This application-driven, compact, automated cell imaging system provides an all-in-one solution for cell counting, cell viability and Cell transfection efficiency through the use of preconfigured biological applications (BioApps). They are specifically optimized for analysis of primary cells from peripheral blood, including PBMC, CAR-T, NK cell and MSC, which commonly used in cell therapy.