Human CD52 is a glycosylphosphatidylinositol (GPI)--anchored antigen expressedon the all lymphocytes as well as within the male genital tract, where it can be produced by epithelialcells of the distal epididymis and duct deferens. CD52 can be shed into seminal plasma and then acquiredby sperm cells during their passage through the genital tract, thus it is detectable on the surface ofepididymal sperm and in the ejaculate but not on either spermatogenetic cells or testicular spermatozoa.Protein core of the sperm and lymphocyte CD52 is identical and it is a product of a single copy genelocated on chromosome 1. However, N-linked carbohydrate side chains (attached to Asn-3) and GPI-anchorstructure are different. Physiological role of CD52 on lymphocytes is unclear, although antibody directedto CD52, CAMPATH-1, is capable of complement activation and it can be clinically useful to treat lympho-proliferativedisorders and to deplete lymphocytes in bone marrow transplants. Monoclonal antibodies directed againstsperm CD52 may cause sperm immobilisation and agglutination and affect hamster oocyte penetration suggestingan association of this molecule with fertilisation.

Keywords: Glycocalyx, Antigens, sperm glycoproteins, CD52