Monoclonal antibody GB17 recognizes human syncytiotrophoblast

A monoclonal antibody, GB17, was obtained from a hybridoma produced following murine immunization with isolated human term syncytiotrophoblastic microvilli. Immunohistological studies demonstrated the GB17 antigen to be present on syncytiotrophoblast of human term, first- and second trimester placenta, but not on human extravillous trophoblast or baboon placental trophoblast. Other normal adult human tissues and transformed cell lines tested were non-reactive with this antibody. Radio-iodinated term syncytiotrophoblastic microvillous protein was immunoprecipitated by GB17, and shown by sodium dodecyl sulfate--polyacrylamide gel electrophoresis to migrate as a single protein band at 175 kDa. The restricted tissue specificity suggests that the GB17 antigen could be useful for the development of a contragestational vaccine.