Anti-Mouse CD3E Antibody (500A2) is a monoclonal inhibitory antibody targeting the mouse CD3ε subunit. CD3ε is a 20-kD transmembrane protein belonging to the immunoglobulin superfamily, primarily expressed on the surface of T cells and NK-T cells, and exhibiting differential expression at various stages of thymocyte differentiation. CD3ε can assemble with CD3δ, CD3γ, and CD3ζ chains, as well as TCR α/β or γ/δ chains, to form TCR complexes. By recognizing peptide-MHC antigen complexes, CD3 plays a critical role in TCR signal transduction, T-cell activation, and antigen recognition.