Semen specific γ-glutamyltransferase carries ABH antigens: a sandwich ELISA for simultaneous semen detection and its ABO blood typing

Abstract Semen type of γ-glutamyltransferase (γ-GTP) is different from the membrane bound type of the enzyme in both biochemical and immunological properties, and consists of two subunits (150 and 95 kDa). We found that anti-ABH antibodies recognize a 150-kDa subunit of seminal γ-GTP by Western blot and immunoprecipitation analyses. Using SG2, one of anti-semen specific γ-GTP monoclonal antibodies which we had produced, and anti-ABH antibodies, we established a sandwich ELISA for identifying human seminal γ-GTP and its ABO type simultaneously. This sandwich ELISA allows ABO typing of highly diluted semen. The dilutions for ABO typing were 10 5 times for A or O, and 10 4 times for B. Furthermore, ABO typing of semen was successfully performed by this ELISA, even in the mixed presence of vaginal fluid, saliva and blood. Thus, seminal γ-GTP carries ABH antigens and the sandwich ELISA with SG2 and anti-ABH antibodies enables ABO typing of semen. The sandwich ELISA is extremely useful for ABO typing originated from semen in the mixture of biological fluids.