CD274 Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human near-haploid HAP1 cell line, engineered for loss of CD274 (Programmed Death-Ligand 1, PD-L1) expression. This product comprises a heterogeneous pool of gene-disrupted cells, collectively abolishing functional CD274 protein while preserving the polyclonal nature advantageous for studying population-level phenotypes without clonal artifacts. The knockout model is generated using CRISPR/Cas9-mediated gene disruption, providing a robust tool for investigating PD-L1 biology in a simplified genetic background.
The HAP1 cell line is a near-haploid human cell line derived from a chronic myeloid leukemia patient. Its near-haploid karyotype reduces genetic redundancy, facilitating genotype-phenotype correlations. As a leukemic hematopoietic line, HAP1 retains signaling networks relevant to immune regulation and oncogenesis, providing a cancer-relevant context for checkpoint studies. The cells are adherent and compatible with diverse functional assays.
CD274 encodes PD-L1, an immune checkpoint ligand that binds PD-1 (PDCD1) on T cells to inhibit activation. Expression is induced by interferon-gamma via JAK-STAT signaling and regulated by MYC and HIF-1??. PD-L1 engagement recruits SHP-2 phosphatase (PTPN11), which dephosphorylates TCR kinases LCK and ZAP70, suppressing PI3K-AKT and RAS-MEK-ERK pathways. PD-L1 also interacts with CD80. Knockout of CD274 removes this inhibitory checkpoint, preventing TCR signal attenuation and enabling study of immune activation mechanisms.
In the HAP1 leukemic background, CD274 knockout eliminates a key immune evasion mechanism. This polyclonal model enables study of restored T-cell reactivity in co-culture and cell-autonomous signaling effects. The near-haploid genome simplifies phenotypic interpretation, ensuring effects are attributable to gene disruption. It is valuable for investigating PD-L1 in hematopoietic malignancies where its overexpression drives immune escape and therapeutic resistance.
Typical applications include immune checkpoint research, T-cell activation assays, and drug screening for PD-L1 inhibitors. Co-culture with T cells allows measurement of proliferation, cytokine secretion, and activation markers. Cells serve as a genetic control for inhibitor validation. Representative assays include flow cytometry, western blotting for phospho-ZAP70, immunofluorescence, and RT-qPCR. For technical support and further information, please contact Ascent Research.
