Poster: Screening Ex Vivo Conditions that Increase Memory T Cell Frequency using High Throughput Flow Cytometry and an Optimized Multiplexed Assay

A critical process in bio-manufacturing of adoptive cell therapies such as chimeric antigen receptor (CAR) T and tumor infiltrating lymphocyte (TIL) therapies is the ex vivo expansion of T cells. Recent clinical studies show a correlation between ex vivo expansion and persistence of infused T cells and patient outcomes. Additional studies show that a subset of functional memory T cells including T memory stem cells (Tscm), central memory T cells (Tcm) and other less differentiated T cell subsets are responsible for long-term anti-tumor responses. This suggests that ex vivo T cell expansion protocols generating higher percentages of Tscm and Tcm in the total cell product are critical to significant clinical improvements in adoptive cell therapies.

To address the need to monitor T cell phenotype and function for improved ex vivo expansion protocols where profiling of memory subsets is crucial, we developed a robust, high content T memory cell and cytokine profiling assay. This miniaturized assay uses high throughput flow cytometry to measure memory cell phenotype, cell viability and effector cytokine release in the same sample well of a 96- or 384-well microtiter plate. The optimized antibody panel includes markers to identify T cells (CD3, CD4, and CD8), markers to discriminate between naive, memory, and effector subsets (CD45RA, CD45RO, CD62L, CD95 and CD27). In addition, secreted cytokine quantitation (IFNγ and IL-10) is performed simultaneously in the same cell | bead-based assay.