Optimizing Transfection- and Transduction-Free siRNA Delivery and Gene Expression Knockdown in Primary Human CD4+ T Cells

T-cell-based therapies have gained momentum in recent decades, revolutionizing treatment options for cancer patients. Currently, CRISPR Cas-9 and RNAi technologies are commonly employed for understanding genetic networks in primary T cells. These technologies involve mainly electroporation or viral vectors to deliver the cargo required for gene editing or silencing and they pose some limitations such as reduced cell viability, poor transfection efficiency, and insertional mutagenesis. Dharmacon™ has developed chemically modified self-delivering siRNAs termed Accell™ siRNAs with wide cell type applicability transcending the need for transfection reagents or viral vectors for intracellular siRNA delivery. In this study, using human primary CD4-T cells as a model, we optimized Accell™ siRNA uptake and gene expression knockdown in unstimulated T cells and optimized a workflow to efficiently knockdown gene expression in primary T cells without compromising cell viability. This method is useful for rapidly investigating gene functions in primary T cells in a resting state.