Recombinant Human CD3 epsilon/CD3E Protein (C-His)

Measured by functional ELISA. Immobilized recombinant human CD3 epsilon binds the reference anti-CD3 antibody OKT3/muromonab with an EC50 in the range of 10–50 ng/mL.

CD3 epsilon is the pivotal signaling subunit of the T-cell receptor complex: together with CD3γ, CD3δ and the ζ chains it couples antigen recognition to intracellular activation through its ITAM motifs, and its extracellular domain carries the epitopes targeted by the first therapeutic monoclonal antibody ever approved (OKT3/muromonab). CD3 epsilon has since become the workhorse arm of T-cellRedirecting bispecifics — blinatumomab, teclistamab, talquetamab and a deep clinical pipeline pair an anti-CD3 arm with a tumor-targeting arm to draw cytotoxic T cells to cancer cells. Because CD3-engagement affinity shapes both potency and cytokine toxicity, recombinant CD3 epsilon is indispensable for bispecific screening, affinity tuning, potency assays and anti-CD3 reagent calibration.