The T-Cell Receptor (TCR) is found on the surface of T-cells and is responsible for recognizing antigens bound to MHC (Major Histocompatibility Complex) molecules. Activation of the TCR results in activation of downstream NFAT signaling. The TCR consists of a heterodimer of two different protein chains, of which the alpha (alpha) and beta (beta) chains are the predominant chains. The TCR CRISPR Lentiviruses are replication incompetent, HIV-based VSV-G pseudo-typed lentiviral particles that are ready to be transduced into almost all types of mammalian cells, including primary and non-dividing cells. The particles contain a CRISPR/Cas9 gene driven by an EF1a promoter, along with 4 sgRNA (single guide RNA) targeting human TRAC (T-Cell Receptor Alpha Constant) and human TRBC1 (T-Cell Receptor Beta Constant 1) regions of the alpha and beta chains. The integrating lentivirus integrates randomly into the cell"s genome to express both the Cas9 and sgRNA. Puromycin selection increases the knockout efficiency by forcing high expression levels of both Cas9 and the sgRNA, and can be used with the integrating lentivirus to quickly and easily achieve high knockdown efficiencies in a cell pool. Efficiencies also depend on the cell type and the gene of interest.