The CD3E/CD3 epsilon 1-27 peptide is critical in the TCR-CD3 complex, transmitting signals during T cell activation. When APC activates the TCR, CD3E undergoes LCK/FYN-mediated phosphorylation together with ITAM, initiating downstream signaling. CD3 epsilon Protein, Cynomolgus (HEK293, Fc) is the recombinant cynomolgus-derived CD3 epsilon protein, expressed by HEK293 , with C-Fc, C-hFc labeled tag.