The CD3E Knockout Jurkat Polyclonal Cells product from Ascent Research is a heterogeneous population of cells derived from the Jurkat T-lymphocyte line, engineered via CRISPR/Cas9-mediated gene disruption to ablate the expression of CD3E. This polyclonal knockout pool is generated without single-cell cloning, providing a representative loss-of-function model that captures the genetic diversity typical of edited cell populations. The product is supplied as a ready-to-use vial of early-passage cells, designed for researchers seeking to interrogate T-cell receptor (TCR) signaling without the constraints of monoclonal artifacts.
Jurkat cells are a widely utilized human T-cell leukemia line, originally established from the peripheral blood of a 14-year-old male with acute T-cell leukemia. This immortalized cell line recapitulates many aspects of mature T-lymphocyte biology, particularly inducible signaling cascades downstream of the TCR. Jurkat cells express key components of the TCR complex and are a cornerstone model for dissecting antigen-mediated activation, cytokine production, and signal transduction pathways relevant to both normal lymphocyte function and leukemogenesis.
The CD3E gene encodes the epsilon chain of the CD3 complex, a critical subunit that, together with CD3-gamma, CD3-delta, and CD3-zeta, assembles with the TCR-alpha/beta heterodimer to form the complete antigen receptor on the T-cell surface. Upon engagement of the TCR by peptide-major histocompatibility complex (pMHC), the Src-family kinases Lck and Fyn phosphorylate immunoreceptor tyrosine-based activation motifs (ITAMs) within CD3 chains, creating docking sites for the kinase ZAP-70. This initiates a signaling cascade involving adaptor proteins LAT and SLP-76, leading to activation of phospholipase C?Cgamma 1 (PLCgamma1), the Ras?CGRB2?CSOS axis, and downstream kinases Raf, MEK, and ERK. These events culminate in the activation of transcription factors NFAT, NF-kB, and AP-1, which drive the expression of key effector molecules such as interleukin-2 (IL-2) and the activation marker CD69. CD3E is indispensable for surface expression of the TCR; its disruption dismantles the entire complex, rendering cells unresponsive to TCR-dependent stimulation.
In the Jurkat background, CD3E knockout provides a powerful system for investigating TCR-proximal signaling events. Without CD3E, Jurkat cells fail to present the TCR on the plasma membrane, abrogating all downstream responses to pMHC or antibody-mediated receptor crosslinking. This model is thus instrumental for studying the structural requirements of CD3 assembly, the dynamics of ITAM phosphorylation, and the recruitment of ZAP-70 to the plasma membrane. Moreover, it allows researchers to distinguish TCR-dependent from TCR-independent signaling branches, contributing valuable insights into T-cell acute lymphoblastic leukemia (T-ALL) biology and the molecular etiology of severe combined immunodeficiency (SCID) linked to CD3 deficiency.
Typical applications of these CD3E knockout polyclonal Jurkat cells include mechanistic studies of the TCR signaling network, screening for chemical or biological modulators of T-cell activation, functional validation of candidate genes in TCR-dependent pathways, and drug sensitivity assays in a TCR-null context. Compatible assays span Western blotting for CD3E, flow cytometry for surface CD3 expression, IL-2 ELISA following stimulation, phospho-ERK flow cytometry, T-cell proliferation measurements, and NFAT reporter systems. For further information on lot-specific characteristics and experimental recommendations, please contact Ascent Research.
