Molecular Classification
Glycoprotein (cell surface), GPI (glycosylphosphatidylinositol)-anchored membrane protein, CD molecule (Cluster of Differentiation family)
Other Names
CAMPATH-1 antigen, Cluster of differentiation 52, CDW52, Cambridge pathology 1 antigen, Epididymal secretory protein E5, HE5, Human epididymis-specific protein 5
Disease Roles
Cancer (notably chronic lymphocytic leukemia and other lymphomas)Infection/Immunosuppression contexts (organ transplantation)

CD52 molecule Overview

CD52, also known as the CAMPATH‑1 antigen, is a small glycoprotein anchored to the cell membrane via a glycosylphosphatidylinositol (GPI) anchor. It is encoded by the CD52 gene located at chromosome 1p36.11. The mature human protein consists of approximately 12–18 amino acids after cleavage from its signal peptide and post-translational modifications. CD52 is highly expressed on the surface of most mature lymphocytes—including T cells, B cells—as well as monocytes, dendritic cells, and spermatozoa within the male genital tract. Its primary clinical significance lies in being targeted by therapeutic monoclonal antibodies such as alemtuzumab for treatment of chronic lymphocytic leukemia, multiple sclerosis relapses unresponsive to first-line agents, organ transplantation rejection prophylaxis, and certain myelodysplastic syndromes or acute myeloid leukemias where it serves both as a drug target and prognostic biomarker. The main mechanism involves antibody-mediated lysis or depletion of CD52-expressing immune cells; this underlies both its efficacy in disease control and its major safety concern—profound immunosuppression with attendant infection risk.

Mechanism of Action

Antibody-dependent cellular cytotoxicity and complement-mediated lysis via binding to CD52 on target cells by monoclonal antibodies such as alemtuzumab

Biological Functions

Immune response modulation (expressed on mature lymphocytes, monocytes, dendritic cells)
Potential antiadhesion function facilitating cell mobility

Disease Associations

Cancer (notably chronic lymphocytic leukemia and other lymphomas)
Infection/Immunosuppression contexts (organ transplantation)

Safety Considerations

  • Profound immunosuppression leading to increased risk of infections due to depletion of mature lymphocytes during therapy with anti-CD52 antibodies like alemtuzumab

Interacting Drugs

Alemtuzumab

Associated Biomarkers

Biomarker
Prognostic marker for certain leukemias and myelodysplastic syndromes; expression correlates with poor survival in some cases of MDS/AML
Used for patient selection in therapies involving alemtuzumab