Immunodetection of living trophoblast.

BACKGROUND: Human chorionic gonadotropin, the pregnancy hormone, is synthesized 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 monoclonal antibody to hCG. Anti-mouse immunoglobulin G with a fluorescent marker was then added. RESULTS: Syncytiotrophoblast stained positive on the external surface of the cell, while controls of leukocytes, endometrial cells and hepatocytes were negative. CONCLUSION: The hCG monoclonal antibody may be used to specifically detect hCG on the surface of living trophoblast in vitro.