Adoptive T cell immunotherapy is an important cancer treatment strategy in which genetically modified T cells are made tumour-specific and activated via introduction of a transgenic antigen receptor, which improves their ability to recognise and destroy tumours. When assessing the efficacy of engineered transgenic T cell receptor (TCR) constructs it is desirable to use cellular reporter systems devoid of endogenous TCR expression. This talk will describe the development of a novel TCR αβ KO (knockout) T Cell Activation Bioassay based on the use of a genetically engineered Jurkat T cell line with endogenous TCR α and β chains knocked out using CRISPR/Cas9. Data will be presented to demonstrate that activation of transgenic TCR-expressing TCRαβ-KO Cells by cognate peptide and major histocompatibility complex (MHC)-expressing antigen-presenting cells (APCs) results in potent TCR activation and promoter-mediated luminescence. For functional assessment of engineered or primary CD8+ T cells a new homogenous immunoassay detection platform for direct ‘in-well’ IL-2 and IFN-γ measurement will also be described in addition to a recently introduced microplate-based target cell killing assay for T-Cell Dependent Cytotoxicity (TDCC) and engineered CAR-T cell killing assays in mixed co-cultures.