The CCL4 Knockout HAP1 Polyclonal Cells product consists of a population of HAP1 cells that have been subjected to CRISPR/Cas9-mediated gene disruption of the CCL4 locus. As a polyclonal knockout cell population, these cells collectively harbor heterogeneous edits that abolish functional CCL4 expression, providing a robust loss-of-function model without clonal selection bias.
The host cell line, HAP1, is a near-haploid human cell line originally derived from the KBM-7 chronic myeloid leukemia line. Its near-haploid karyotype simplifies genetic analysis and makes it a valuable model for studying gene function and signaling pathways. HAP1 cells maintain stable growth characteristics and are widely used in functional genomics, drug screening, and mechanistic studies.
The CCL4 gene encodes macrophage inflammatory protein-1?? (MIP-1??), a member of the CC chemokine family that functions as a potent chemoattractant for immune cells. CCL4 is transcriptionally induced by inflammatory stimuli such as TNF-??, IL-1??, and IFN-??, particularly in activated T cells via TCR/CD3 engagement and CD28 costimulation, with NF-??B serving as a key downstream transcription factor. Upon secretion, CCL4 binds primarily to the CCR5 chemokine receptor, a G-protein-coupled receptor that initiates intracellular signaling cascades. Ligand-receptor engagement promotes G protein activation, leading to PI3K/Akt and MAPK/ERK pathway stimulation, calcium mobilization, and activation of small GTPases such as RAC1. These events culminate in actin polymerization and directed cell migration. Additionally, CCL4 competes with HIV gp120 for CCR5 binding, thereby acting as a natural HIV-suppressive factor. The knockout of CCL4 in this polyclonal cell population disrupts these signaling axes, abolishing CCL4-dependent chemotaxis and downstream effector functions.
The HAP1 cell line offers a simplified genetic background that facilitates the interpretation of knockout phenotypes. In the context of CCL4 disruption, HAP1 cells provide a clean system to study chemokine signaling without the confounding effects of a diploid genome. Although HAP1 cells are derived from a leukemic background, they retain expression of many signaling components relevant to chemokine biology, making the CCL4 knockout in this host a valuable tool for investigating CCR5-mediated signaling, HIV entry mechanisms, and leukocyte migration pathways. This model enables researchers to attribute phenotypic changes directly to the loss of CCL4 function.
Researchers can employ the CCL4 Knockout HAP1 Polyclonal Cells in a variety of assay formats, including chemotaxis assays to evaluate migratory defects, qPCR and western blotting to confirm gene and protein expression changes, and flow cytometry to assess CCR5 surface levels. The cells are particularly suited for HIV pseudovirus entry assays to study viral tropism and for screening CCR5 antagonists in drug discovery programs. Intracellular calcium flux measurements can further delineate signaling defects downstream of CCR5. This polyclonal knockout population serves as a robust in vitro model for investigating inflammatory diseases, cancer metastasis, and immune cell trafficking. For further details, please contact Ascent Research.
