The CD19 Knockout HAP1 Polyclonal Cells consist of a CRISPR/Cas9-edited population of HAP1 near-haploid human cells harboring a targeted disruption in the CD19 locus. By eliminating CD19 expression, this polyclonal model enables interrogation of B-cell co-receptor function in a simplified genetic background. The polyclonal format circumvents clonal variation and ensures a representative range of editing outcomes for consistent experimental performance.
HAP1 is a near-haploid male cell line derived from the KBM-7 chronic myeloid leukemia (CML) blast crisis line. Its haploid karyotype facilitates unambiguous genotype?Cphenotype correlations in genetic screens and drug target studies. HAP1 is widely employed in CRISPR-based functional genomics and retains features relevant to hematopoietic malignancy modeling, making it a preferred host for dissecting signaling pathways pertinent to leukemia and lymphoma.
CD19 is a membrane glycoprotein that functions as a co-receptor for the BCR, enhancing signal transduction by forming a complex with CD21, CD81, and CD225. Upon complement C3d-mediated antigen presentation, Lyn kinase phosphorylates CD19, which recruits PI3K via its p85 subunit and triggers downstream activation of AKT, PLC??2, Vav, and the MAPK/ERK and NF-??B cascades. Transcription of CD19 is governed by PAX5 and EBF1, and its engagement promotes B-cell proliferation and antibody production. Knockout of CD19 attenuates PI3K/AKT and NF-??B signaling, impairing BCR signal amplification.
In the HAP1 near-haploid background, CD19 knockout provides a streamlined system to dissect BCR signaling components without redundant gene copies. This model is particularly useful for haploid genetic screens aimed at identifying synthetic lethal interactions or signaling dependencies associated with CD19 loss. While HAP1 originates from a myeloid lineage, its genetic amenability and hematopoietic derivation make it a valuable platform for studying CD19-dependent pathways when combined with appropriate stimuli or ectopic expression of pathway members. The polyclonal nature reduces selection bias, enabling population-level analyses of CD19 function.
These polyclonal knockout cells support diverse applications, including CRISPR-based functional screening for BCR pathway modulators, validation of CD19-targeted immunotherapies (e.g., CAR-T, bispecific antibodies), and functional genomics of B-cell signal transduction. Representative assays encompass genomic DNA sequencing, T7E1 mismatch detection, western blotting, flow cytometry, RT-qPCR, complement-dependent cytotoxicity (with CD19-reconstituted models), and CAR-T killing co-culture assays. The cells also serve as a robust negative control in CD19 expression studies. For further technical information, please contact Ascent Research.
