| 背景 | This antibody is the OKT-3 clone, one of the most widely used and best-characterised anti-human CD3 monoclonal antibodies, presented here in a recombinant chimeric format (mouse IgG2a CH1 and kappa constant regions fused to human IgG1 CH2+CH3). It reacts with human CD3 and targets the CD3 epsilon chain of the TCR/CD3 complex. The clone is well suited to functional T-cell research because engaging CD3 delivers a potent activation signal to T lymphocytes, making OKT-3 a standard reagent for polyclonal T-cell stimulation, expansion, and receptor-modulation studies. Supplied as a low-endotoxin (research-grade less than 1 EU/mg, or ultra-low less than 0.5 EU/mg), bulk-available (milligram to gram scale) preparation, it is intended for in-vitro functional assays, ex-vivo T-cell culture, and related research applications. The chimeric constant-region design allows Fc engagement and detection flexibility while retaining OKT-3 binding specificity. For research use only (RUO); not for diagnostic or therapeutic use.
CD3 epsilon (CD3e) is an invariant subunit of the CD3 complex, which associates non-covalently with the clonotypic T-cell receptor (TCR) alpha/beta (or gamma/delta) heterodimer to form the TCR/CD3 signalling complex on the surface of T lymphocytes. The full complex comprises CD3 gamma, delta, epsilon and the zeta homodimer; CD3e pairs with both gamma and delta. Because the TCR itself has only short cytoplasmic tails, the CD3 chains carry the immunoreceptor tyrosine-based activation motifs (ITAMs) that transduce antigen-recognition signals. Upon TCR engagement, ITAM phosphorylation by Lck recruits ZAP-70, initiating downstream signalling that drives T-cell activation, proliferation, and effector differentiation. CD3e is expressed on essentially all mature T cells and thymocytes, making it a canonical pan-T-cell marker and a key handle for experimentally triggering or modulating T-cell responses. |
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