CD8a (Ly 2.1) Antibody – Mouse Monoclonal

The CD8 antigen is a cell surface glycoprotein found on most cytotoxic T lymphocytes that mediates efficient cell-cell interactions within the immune system. The CD8 antigen acts as a coreceptor with the T-cell receptor on the T lymphocyte to recognize antigens displayed by an antigen presenting cell in the context of class I MHC molecules. The coreceptor functions as either a homodimer composed of two alpha chains or as a heterodimer composed of one alpha and one beta chain. Both alpha and beta chains share significant homology to immunoglobulin variable light chains. This gene encodes the CD8 alpha chain. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Nov 2011]

Function: Identifies cytotoxic/suppressor T-cells that interact with MHC class I bearing targets. CD8 is thought to play a role in the process of T-cell mediated killing. CD8 alpha chains binds to class I MHC molecules alpha-3 domains.

Subunit structure: In general heterodimer of an alpha and a beta chain linked by two disulfide bonds. Can also form homodimers. Shown to be expressed as heterodimer on thymocytes and as homodimer on peripheral blood T-lymphocytes. Interacts with the MHC class I HLA-A/B2M dimer. Interacts with LCK in a zinc-dependent manner. Ref.9

Subcellular location: Isoform 1: Cell membrane; Single-pass type I membrane protein. Isoform 2: Secreted.

Post-translational modification: All of the five most C-terminal cysteines form inter-chain disulfide bonds in dimers and higher multimers, while the four N-terminal cysteines do not

By similarity.

Involvement in disease: Familial CD8 deficiency (CD8 deficiency) [MIM:608957]: Novel autosomal recessive immunologic defect characterized by absence of CD8+ cells, leading to recurrent bacterial infections.Note: The disease is caused by mutations affecting the gene represented in this entry.

Sequence similarities: Contains 1 Ig-like V-type (immunoglobulin-like) domain.