Cd3

Specific marker for Pan-T cells. The antibody also binds to thymocytes, Purkinje cells (cerebellum).

Structure: Complex of 5 unvarying polypeptide chains (25-28, 21, 20, 16 and 22 kDa)

Application: FACS, IHC (P) (G), IF

CD3 is part of a larger complex that includes the T cell receptor(TCR). CD3 consists of transmembrane proteins belonging to the immunoglobulin superfamily. The transmembrane domain of the CD3 complex is negatively charged and thus allows binding to the TCR.

The cytosolic portion of CD3 contains highly conserved peptide segments called "immunoreceptor tyrosine-based activation motifs" (short: ITAM). ITAMs are important components of the intracellular signaling pathway associated with CD3 TCR. Activation of the TCR leads to phosphorylation of the intracellular portion of CD3, which initiates the signaling cascade.

In neoplastic T cell soft tissue, CD3 antigen loss is often observed.

Standard value: The standard values of T-cells are
between 1.700 - 3.600/µlimin the
1st year
2 - 6th year between 1.800 - 3.000/µlim
7 - 17th year between 1.400 - 2.000/µlin the



18th year between 900 - 2.300/µl

There are 4 subtypes of CD3, including CD3δ, CD3ε, CD3γ, and CD3ζ CD3δ/CD3ε and CD3γ/CD3ε can form the TCR-CD3 complexes through the α/β-chain of TCR as heterodimers. CD3-targeted therapeutic antibodies usually recognize the CD3ε in the heterodimer complex to activate the anti-tumor activity of T cells. See also BITE antibodies.

1. Hantschke M et al (2016) Immunohistological techniques. In: L. Cerroni et al. histopathology of the skin. Springer publishing house Berlin-Heidelberg p. 26-33.