DEMONSTRATION OF DOSE-DEPENDENT CYTOTOXIC ACTIVITY IN CANCER-CELLS BYSPECIFIC HUMAN CHORIONIC-GONADOTROPIN MONOCLONAL-ANTIBODIES

BACKGROUND, Previous studies in which monoclonal antibodies (MoAbs) we re used against different epitopes of human chorionic gonadotropin (hC G) demonstrated the presence of membrane-associated hCG and its subuni ts by cancer cells of different types and origins and by human embryon ic and fetal cells. To elucidate the mechanism of action of a syntheti c vaccine against hCG, experiments were conducted to determine the pre sence or absence of direct dose dependent cytolytic activity by hCG Mo Abs, including those elicited by the vaccine. METHODS. Human adenocarc inoma cells from the uterine cervix (ATCC HeLa CCL 2.0) grown in defin ed media at 37 degrees C were treated for 2-3 days with different sele cted doses of each of 12 MoAbs directed against different epitopes of hCG. Three of these MoAbs were against three different epitopes of the synthetic hCG beta vaccine. RESULTS. There was a direct dose dependen t effect by a MoAb directed against the natural hCG beta carboxy termi nal peptide (CTP), by a MoAb directed against hCG alpha, and by one of the three MoAbs produced by the synthetic hCG beta-CTP, which is the main component of the World Health Organization (WHO) vaccine being te sted for fertility control and for cancer treatment or prevention. CON CLUSIONS. For the first time (to the authors' knowledge), these result s show the existence of hCG MoAbs that have direct dose related cytoto xicity at 37 degrees C and explain the mechanism of action of the WHO anti-hCG vaccine. Cancer 1998;83: 783-7. (C) 1998 American Cancer Soci ety.