Immunodetection of living trophoblast

Background: Human chorionic gonadotropin, the pregnancy hormone, is synthes ized by trophoblast cells which make up the placenta. Objective: To determine whether antibody to hCG can be used to specifically detect living trophoblast in vitro by binding to the external membrane. Methods: Trophoblast was isolated from fresh placentas of women undergoing termination of pregnancy in the first trimester and incubated with monoclon al antibody to hCG. Anti-mouse immunoglobulin G with a fluorescent marker w as then added. Results: Syncytiotrophoblast stained positive on the external surface of th e cell, while controls of leukocytes, endometrial cells and hepatocytes wer e negative. Conclusion: The hCG monoclonal antibody may be used to specifically detect hCG on the surface of living trophoblast in vitro.