title: Epitope analysis for human sperm-immobilizing monoclonal antibodies, MAb H6-3C4, 1G12 and campath-1.
abstract: Human monoclonal antibody, MAb H6-3C4, possesses strong sperm immobilizing activity. MAb H6-3C4 has been suggested by several research groups to react with a carbohydrate moiety of male reproductive tract CD52 (mrtCD52). In the present study, we analysed the epitope on mrtCD52 for MAb H6-3C4 and found that it was polymorphic in Western blot analysis and disappeared after enzymatic removal of the N-linked carbohydrate moiety. Two other monoclonal antibodies (1G12, campath-1) with sperm-immobilizing activity recognized mrtCD52 in a polymorphic manner similar to MAb H6-3C4. Further analysis showed that 1G12 recognized a structure formed by the peptide and/or a glycosylphosphatidylinositol (GPI) anchor portion as does campath-1. Results of a lectin binding assay suggested the presence of O-linked carbohydrates on mrtCD52. Our results also indicated that the peptide portion of CD52 could serve as an epitope for sperm-immobilizing antibodies. It was concluded that the epitope of MAb H6-3C4 is similar to, but distinct from, those of 1G12 and campath-1, and that mrtCD52 contains different antigenic epitopes.
authors.affiliation: Laboratory of Developmental Biology and Reproduction, Institute for Advanced Medical Sciences, Nishinomiya, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Hasegawa
authors.forename: Y
authors.initials: Y
authors.lastname: Fu
authors.forename: H
authors.initials: H
authors.lastname: Tsubamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Tsuji
authors.forename: H
authors.initials: H
authors.lastname: Sawai
authors.forename: S
authors.initials: S
authors.lastname: Komori
authors.forename: K
authors.initials: K
authors.lastname: Koyama
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D015703:Antigens, CD / Q000737:chemistry / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000276:immunology*; D000074301:CD52 Antigen; D000939:Epitopes / Q000276:immunology*; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D008297:Male; D013094:Spermatozoa / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000074301:CD52 Antigen; C000613862:CD52 protein, human; D000939:Epitopes; D006023:Glycoproteins