Cluster of differentiation 52 sperm-specific glycoform (CD52g)

Cluster of differentiation 52 sperm-specific glycoform (CD52g), also known as SAGA-1, is a small glycosylphosphatidylinositol (GPI)-anchored glycoprotein essential for male reproductive function. While the CD52 protein backbone is expressed on both lymphocytes and sperm, the CD52g glycoform is uniquely synthesized in the epididymal epithelium and acquired by sperm during their passage through the epididymis (UniProt P31358; Diekman et al., 1998). This sperm-specific version is characterized by complex, highly branched carbohydrate structures that differ significantly from those found on white blood cells (Anderson et al., 2021). Biologically, CD52g is involved in protecting sperm from the female immune system and facilitating sperm-egg recognition and binding (Norton et al., 2002). It is a prominent target for non-hormonal contraception, as antibodies directed against its unique glycan epitopes can cause rapid sperm agglutination and prevent fertilization without depleting systemic lymphocytes (Anderson et al., 2021). Current research focuses on developing monoclonal antibodies, such as the Human Contraceptive Antibody (HCA), for topical or systemic contraceptive use (Science Translational Medicine, 2021).

Other names

SAGA-1Sperm agglutination antigen 1HE5Human epididymal gene 5 productGPI-anchored sperm antigen

Induction of sperm agglutination and immobilization, and inhibition of sperm-zona pellucida binding through targeted binding of sperm-specific carbohydrate epitopes.