Cellular Retention Assay to Determine the Interaction Frequency of CD19-directed Chimeric Antigen Receptor (CAR) Engineered Cells against CD19+ Leukemic Cells

Abstract

Cancer recognition by chimeric antigen receptor T (CAR-T) cell is prerequisite for cancer killing to occur. Anomalies in the binding specificity of scFv in the CAR construct may prevent successful eradication of these cancer cells. In some cases, these anomalies (i.e., altered specificity) may cause deleterious effects such as on-target off-tumor toxicity or on-set CAR-T cell activation that may lead to life-threatening complications. We describe in this assay an easy, flexible and cheap way of analyzing target specificity of CAR-engineered cells toward cancer in the context of cell-to-cell interaction that can be used to screen other antigen-specific CARs. We are coining this test as cellular retention assay.