RNAscope™ to detect immune cells presented at AACR 2020

The ability of T cells to mediate anti-tumor immunity has been harnessed to develop some of the most successful immunotherapies in recent years. Although direct presentation of tumor antigens by tumor cells plays an important role in the effector function of cytotoxic T lymphocytes (CTLs), cross-presentation by professional antigen presenting cells such as dendritic cells (DCs) is vital for priming naive CD8+ T cells and developing a sustainable cytotoxic response. Natural killer (NK) cells within the tumor microenvironment (TME) recruit a specific population of DCs called conventional type 1 DCs (cDC1s) into the TME by secreting chemokines such as CCL5 and XCL1. However, these cells are very low in abundance and are characterized by the expression of numerous markers, making their detection in the tissue context challenging.

By utilizing the RNAscope Multiplex ISH assay we were able to identify and visualize the spatial relationship between NK cells, CTLs, and cDC1 cells, a rare subset of DC cells that excel at presenting tumor antigens to T cells. Using this technology, it is possible to spatially interrogate the TME and detect specialized immune cells when assessing response to immunotherapies.