T-cell surface glycoprotein CD3 epsilon chain (CD3E) (CD3E)

The T-cell surface glycoprotein CD3 epsilon chain (CD3E) is a critical transmembrane protein that functions as a key subunit of the T-cell receptor (TCR)-CD3 complex on the surface of T-lymphocytes [1, 10]. It is essential for the adaptive immune response, as it facilitates the transduction of signals from the TCR to the cytoplasm upon antigen recognition through its immunoreceptor tyrosine-based activation motifs (ITAMs) [1, 8]. CD3E is also vital for the assembly and stable expression of the TCR complex and plays a non-redundant role in T-cell development within the thymus [1, 11]. Clinically, CD3E is a prominent therapeutic target for both immunosuppression and oncology; monoclonal antibodies like muromonab-CD3 and teplizumab modulate T-cell activity to treat transplant rejection and autoimmune diseases, while bispecific T-cell engagers (BiTEs) like blinatumomab recruit T-cells to kill cancer cells [12, 14, 17]. However, the potent activation of T-cells via CD3E can lead to severe adverse effects, most notably cytokine release syndrome (CRS) and neurotoxicity, which require careful clinical management [15, 16, 19]. Genetic defects in CD3E lead to severe combined immunodeficiency, underscoring its indispensable role in maintaining a functional immune system [6, 12].

Other names

CD3e moleculeT3ETCRECD3 epsilon subunit of T-cell receptor complexIMD18CD antigen CD3e

Redirection of cytotoxic T-cells to tumor cells via bispecific antibodies; immunosuppression through T-cell depletion or TCR-CD3 complex internalization; and modulation of T-cell responses via partial agonism.