Antigen-specific therapy of experimental metastases

Abstract

In a methylcholanthrene‐induced tumor (MCA‐F) model in C3H/HeJ mice, curative resection of a progressive tumor promotes artificial lung metastases following intravenous injection of a highly metastatic cell variant designated clone 9‐4. The number of metastatic lung colonies depends upon the status of host immunity at the tumor resection: mice resected 7 or 14 days, but not 28 days after tumor inoculation display significantly retarded postoperative, experimentally induced lung metastases. The number of lung colonies in mice that had tumors resected at 14 days was three times greater than in mice that had 28‐day neoplasms resected. Neither therapy with weekly injection of 50 μg tumorspecific transplantation antigen, which had been extracted using a single phase of 2.5% 1‐butanol (CBE), nor 20 mg/kg cyclophosphamide (CY) alone prevented lung colonization. Assessment of helper‐suppressor ratios in the spleen from mice after tumor surgery showed that CBE administration decreased the ratio in mice after resection of 14‐day tumors, but not after resection of 28‐day tumors. Combined therapy with specific tumor antigen and an antisuppressor cell agent reduced metastases, regardless of the tumor size. Cancer 55:1296‐1302, 1985.