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

Semen type of gamma-glutamyltransferase (gamma-GTP) is different from the m embrane bound type of the enzyme in both biochemical and immunological prop erties, and consists of two subunits (150 and 95 kDa). We found that anti-A BH antibodies recognize a 150-kDa subunit of seminal gamma-GTP by Western b lot and immunoprecipitation analyses. Using SG2, one of anti-semen specific gamma-GTP monoclonal antibodies which we had produced, and anti-ABH antibo dies, we established a sandwich ELISA for identifying human seminal gamma-G TP and its ABO type simultaneously. This sandwich ELISA allows ABO typing o f 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 successf ully performed by this ELISA, even in the mixed presence of vaginal fluid, saliva and blood. Thus, seminal gamma-GTP carries ABH antigens and the sand wich ELISA with SG2 and anti-ABH antibodies enables ABO typing of semen. Th e sandwich ELISA is extremely useful for ABO typing originated from semen i n the mixture of biological fluids. (C) 1999 Elsevier Science B.V. All righ ts reserved.