title: Soluble antigens of IgG receptor Fc gamma RIII in human seminal plasma.
abstract: Human seminal plasma (SP) has been shown to affect several immunologic reactions in vitro. This might be due in part to the presence of proteins that specifically bind the Fc domain of IgG. By using mAb Leu 11a, Leu 11b, Leu 11c, and 3G8 we showed that the Fc binding of SP is associated with a molecule that antigenically resembles Fc gamma RIII. This molecule manifests specific affinity for solid phase-coupled IgG-Fc, and appears not be be cell membrane-associated. When compared with serum or blood plasma, its highest concentration was found in SP. Western blot analysis of SP performed with mAb Leu 11a, Leu 11b, Leu 11c, and 3G8 showed distinct bands at approximately 70 and 35 kDa, which contrasts with the broad area of electrophoretic mobility reported for membrane-bound Fc gamma RIII. These molecules in SP could influence maternal immune responses to paternal Ag during fertilization and pregnancy.
authors.affiliation: Center for Reproduction and Transplantation Immunology, Methodist Hospital of Indiana, Indianapolis 46202.
authors.forename: C J
authors.initials: CJ
authors.lastname: Thaler
authors.forename: W P
authors.initials: WP
authors.lastname: Faulk
authors.forename: J A
authors.initials: JA
authors.lastname: McIntyre
mesh_terms: D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D000943:Antigens, Differentiation / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D001666:Binding Sites, Antibody; D001798:Blood Proteins / Q000378:metabolism; D015153:Blotting, Western; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D011961:Receptors, Fc / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D017452:Receptors, IgG; D015203:Reproducibility of Results; D012661:Semen / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D001798:Blood Proteins; D007074:Immunoglobulin G; D008565:Membrane Proteins; D011961:Receptors, Fc; D017452:Receptors, IgG