MAA & CD3

In immunology, the CD3 (cluster of differentiation 3) T-cell co-receptor is a protein complex and is composed of four distinct chains. In mammals, the complex contains a CD3γ chain, a CD3δ chain, and two CD3ε chains. These chains associate with a molecule known as the T-cell receptor (TCR) and the ζ-chain to generate an activation signal in T lymphocytes. The TCR, ζ-chain, and CD3 molecules together comprise the TCR complex.

A (pre)melanosomal 100 + 7 kd antigen (glycoprotein) present in melanomas, clear cells sarcomas (melanoma of soft tissue), nevocellular nevi, and normal melanocytes. Except for one case of non Hodgkin's lymphoma in which macrophages were positive, the antigen has not been detected with other tumors or tissues observed.