CD52

CD52 is a protein that in humans is encoded by the CD52 gene. It is also known as CAMPATH-1 antigen, a name derived from the monoclonal antibody therapy that binds to this protein. CD52 is a small protein that is present on the surface of mature lymphocytes, including T cells, B cells, and natural killer cells. It is also found on monocytes, macrophages, and eosinophils, and is enriched on sperm cells.

Structure

The CD52 protein is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein that is composed of a 12-amino acid peptide with a 23-amino acid signal peptide. The protein is heavily glycosylated, with more than half of its mass made up of carbohydrate. The GPI anchor attaches the protein to the cell membrane.

Function

The exact function of CD52 is not well understood. However, it is thought to play a role in immune response. The protein is involved in T cell activation and proliferation, and it may also be involved in sperm-egg fusion during fertilization.

Clinical significance

CD52 is the target of the monoclonal antibody alemtuzumab, which is used in the treatment of chronic lymphocytic leukemia (CLL) and multiple sclerosis (MS). Alemtuzumab binds to CD52 and causes the destruction of lymphocytes, thereby reducing the number of abnormal cells in CLL and reducing inflammation and nerve damage in MS.

See also

• Cluster of differentiation
• Monoclonal antibody therapy
• Chronic lymphocytic leukemia
• Multiple sclerosis