The lack of an effect of active immunization with the beta-subunit of chorionic gonadotropin coupled to tetanus toxoid on the growth of human choriocarcinoma maintained in the hamster cheek pouch.

The antitumor properties of antibodies to the beta-subunit of hCG (hCG beta) coupled to tetanus toxoid (tt) were studied in hamsters implanted with the BeWo strain of human choriocarcinoma. After active immunization with hCG beta-tt mixed in complete Freund's adjuvant, hamsters synthesized large quantities of antibodies which bound whole hCG, as measured in vitro by the binding of radiolabeled hCG to plasma. Scatchard binding analysis indicated that the total high affinity hCG-binding capacity of hCG beta-tt plasma was approximately 130 microgram/ml. However, these antibodies were devoid of any antitumor activity. Choriocarcinoma implanted into hamsters during the peak times of [125I]iodo-hCG-binding activity by plasma did not show any change in tumor volume over a 20-day period of tumor growth compared to tumors in hamsters immunized with tt alone. Active immunization with hCG beta-tt did not alter the percentage of tumors taking, the length of lag phase of tumor growth, or the initial day of grossly detectable tumor necrosis. These results suggest that active immunization with hCG beta-tt will not alter the growth of transplantable choriocarcinoma.