CD200 Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population derived from the HAP1 human near-haploid cell line. This heterogeneous pool contains cells with diverse loss-of-function mutations in the CD200 gene, eliminating CD200 protein expression. The polyclonal format captures multiple independent knockout alleles, minimizing single-clone artifacts. This model facilitates robust investigation of the CD200-CD200R immune checkpoint and its downstream signaling consequences.
The HAP1 cell line is a near-haploid human cell line originating from the KBM-7 chronic myeloid leukemia line. With only a single copy of most chromosomes, HAP1 allows complete gene disruption from a single targeting event, streamlining functional genomics studies. It is widely used in CRISPR screens and genetic perturbation assays, and its adherent, stable growth supports high-throughput and co-culture experimental formats.
CD200 is a transmembrane glycoprotein that acts as a ligand for the inhibitory receptor CD200R on myeloid and lymphoid cells. Receptor engagement triggers ITIM-mediated recruitment of adaptor proteins Dok2 and RasGAP, dampening MAPK/ERK and NF-kB signaling and ultimately suppressing immune cell activation. CD200 expression is upregulated by IL-4, IL-10, and TGF-beta via STAT6 or NF-kB pathways. In the knockout cells, absence of CD200 removes this inhibitory constraint, leading to heightened ERK and NF-kB activity and elevated production of pro-inflammatory cytokines such as TNF-alpha and IL-6.
In the near-haploid HAP1 background, the CD200 knockout yields a clean null phenotype devoid of allelic redundancy, ensuring unambiguous functional readouts. Although HAP1 is a myeloid-derived cell line, it can be co-cultured with immune effector cells to reconstitute the CD200-CD200R axis in trans. This setup is particularly valuable for modeling immune evasion in myeloid malignancies, where CD200 is often overexpressed, and for dissecting tumor-immune signaling in a genetically tractable system.
These polyclonal knockout cells are suited for flow cytometric validation of CD200 loss, co-culture immune suppression assays with multiplex cytokine profiling (e.g., TNF-alpha, IL-6), and western blot detection of phospho-ERK and phospho-NF-kB. RT-qPCR can assess transcriptional changes in immune-related genes. Key applications include cancer immune checkpoint studies, autoimmune disease research, and therapeutic target validation for CD200. For technical inquiries, please contact Ascent Research.
