receptor. Like many cell surface receptors/markers,<unk>  is a member of the immunoglobulin superfamily. It has four immunoglobulin domains (D1 to D4) that are exposed on the extracellular surface of the cell: * D1 and D3 resemble immunoglobulin variable (IgV) domains. * D2 and D4 resemble immunoglobulin constant (IgC) domains. The immunoglobulin variable (IgV) domain of D1 adopts an immunoglobulin-like β-sandwich fold with seven β-strands in 2 β-sheets, in a Greek key topology.<unk>  interacts with the β2-domain of MHC class II molecules through its D1 domain. T cells displaying<unk>  molecules (and not<unk> 8) on their surface, therefore, are specific for antigens presented by MHC II and not by MHC class I (they are MHC class II-restricted). MHC class I contains Beta-2 microglobulin. The short cytoplasmic/intracellular tail (C) of<unk>  contains a special sequence of amino acids that allow it to recruit and interact with the tyrosine kinase Lck.
CD4
CD8
CD74
CD86
CD80
CD137
CD22
CDV3 