CD52 antigen (CD52) (CD52)

CD52 is a small, highly glycosylated protein anchored to the cell membrane via a glycosylphosphatidylinositol (GPI) linkage (UniProt: P31358). It is predominantly expressed at high levels on the surface of mature T and B lymphocytes, as well as on monocytes, macrophages, and natural killer cells (PubMed: 28257019). While its exact physiological function remains somewhat elusive, it is believed to play a role in T-cell activation and migration, and it is also found in the male reproductive tract where it associates with sperm (NCBI Gene ID: 1043). CD52 is a significant therapeutic target because its broad expression on immune cells allows for the targeted depletion of these populations in various disease states. The monoclonal antibody alemtuzumab binds to CD52, triggering cell death through complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) (StatPearls: NBK541043). This mechanism is utilized clinically to treat B-cell chronic lymphocytic leukemia and relapsing-remitting multiple sclerosis. However, the profound depletion of lymphocytes associated with CD52-targeted therapy necessitates careful monitoring for secondary autoimmunity and opportunistic infections (FDA Label: Lemtrada).

Other names

CAMPATH-1 antigenCambridge pathology 1 antigenEpididymal secretory protein E5Human epididymis-specific protein 5He5CDW52

Alemtuzumab is a humanized monoclonal antibody that targets the CD52 antigen. Upon binding, it mediates the depletion of CD52-positive cells, primarily lymphocytes, through antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and induction of apoptosis (StatPearls: NBK541043).