Preclinical CAR-T Cell Target Safety, Biodistribution, And Tumor Infiltration Analysis Using The RNAscope® ISH Assay

By Helly Pimentel, Helen Jarnagin, Hailing Zong, Courtney Todorov, Courtney Anderson, Bingqing Zhang, Christopher Bunker, Xiao-Jun Ma; Advanced Cell Diagnostics Inc.,

In this report we illustrate a way to detect activated CAR-T cells in the tissue context, as well as low expression of CAR target antigen, using the RNAscope® in situ hybridization (ISH) technology. CAR-T cells are activated by target antigen engagement even at very low levels of target expression. In order to avoid adverse events resulting from “on-target/off-tumor” toxicity, a highly sensitive and specific gene expression assay is necessary for preclinical target safety assessment. The RNAscope® assays can be incorporated into preclinical CAR-T safety assessment and clinical pharmacokinetic workflows to:

• Detect low levels of gene expression across all normal tissues in animal models and human samples
• Assess cell-specific target expression in normal tissues and expression heterogeneity in tumor tissues
• Visualize and quantify CAR-T cell infiltration and activation in tumor and off-tumor tissues
• Simultaneously detect CAR/TCR vector and cytokines, T cell markers, or other cell-type markers