The CD244 Knockout HAP1 Polyclonal Cells product comprises a heterogeneous population of human HAP1 cells engineered via CRISPR/Cas9-mediated gene disruption to introduce loss-of-function mutations in the CD244 gene. This polyclonal knockout format provides a robust model for studying CD244 function without the constraints of single-cell clonal isolation. The editing targets the CD244 locus, resulting in a mixed pool of edited alleles that collectively abolish the protein??s activity. The cells are suitable for a wide range of downstream applications requiring gene knockout backgrounds, offering a practical tool for functional genomics and immune signaling research.
The HAP1 cell line is a near-haploid derivative of the KBM-7 chronic myeloid leukemia cell line, characterized by a haploid karyotype for most chromosomes, except for a disomic region on chromosome 8. This unique genomic simplicity makes HAP1 cells ideally suited for gene disruption studies, as targeting a single allele is sufficient to generate a complete loss-of-function phenotype. The near-haploid background minimizes genetic redundancy and facilitates straightforward interpretation of knockout effects, establishing HAP1 as a workhorse model for functional genomics, drug screening, and pathway dissection.
CD244, also known as 2B4 or SLAMF4, belongs to the SLAM family of receptors and modulates immune cell activity through its interactions with the ligand CD48. Upon CD48 binding, CD244 recruits the SAP (SH2D1A) or EAT-2 (SH2D1B) adaptor proteins, which in turn engage Src family kinases such as Fyn. This initiates a signaling cascade involving PLC??1, Vav1, and PI3K, leading to ERK activation and downstream transcription of effector molecules including IFN-??, TNF, perforin, and granzyme B. Conversely, in the absence of SAP, CD244 associates with phosphatases like SHP-1, which inhibit activation signals. Thus, CD244 exerts both activating and inhibitory functions depending on the cellular context and adaptor availability, playing a critical role in natural killer cell and CD8+ T cell cytotoxicity and cytokine secretion.
The elimination of CD244 in the HAP1 background enables precise dissection of its role in immune cell processes without interference from other SLAM family members that may have partial redundancy in diploid cells. This model is particularly valuable for studying the regulation of NK cell-mediated cytotoxicity and T cell receptor signaling pathways, which are implicated in autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis), immunodeficiency (X-linked lymphoproliferative disease), and viral infections such as HIV. Moreover, given HAP1??s rapid proliferation and ease of manipulation, the knockout cells facilitate high-throughput screening efforts to identify modulators of the CD244 axis in cancer immunity.
Typical research applications include functional characterization of CD244 in immune receptor signaling, validation of downstream phosphorylation events by phospho-signaling analysis, and co-immunoprecipitation studies to map protein?Cprotein interactions with SAP, EAT-2, Fyn, or LAT. The polyclonal cells are well-suited for flow cytometry-based cytotoxicity assays, gene expression profiling via RT-qPCR, and confirmation of knockout by Sanger sequencing and Western blotting. They also serve as a platform for drug screening targeting immunomodulatory checkpoints. For additional information or to discuss custom requirements, contact Ascent Research.
