Agglutination of murine tumor cells by sera from various cancer patients.

Abstract

Sera from 72 of 94 patients with various malignancies and those from seven of nine pregnant womens agglutinated mouse ascitic tumor cells in vitro. Sera from 15 of 17 benign disease controls also agglutinated the cells, but none of the sera from 21 normal controls did. The agglutination activity of the sera from cancer patients was studied in detail. The activity, which remained after absorption with liver tissue from normal adult mice and also with blood group A substance, was absorbed completely by embryonic tissue of the mouse and partially by perchloric acid soluble fraction (PCAS) of the target cells or by carcinoembryonic antigen (CEA) from human cancer, and therefore was related to cross-reacting tumor-associated embryonic materials. The agglutination was inhibited by monosaccharides such as galactose or N-acetyl glucosamine. The receptor activity of PCAS for the agglutination factors in the sera from cancer patients was also affected by treatment with glycosidases, but not by trypsinization. These results indicated that carbohydrate moieties of the cell surface components were involved in the agglutination. It was thus evident that a sort of humoral reaction took place in cancer patients against tumor-associated embryonic materials on the tumor cell surface, that a considerable part, at least, of such reactions were directed to their carbohydrate moieties and that their teminal sugar residues played the most important role in the reaction. The humoral factors induced by this reaction was located in β-globulin fraction of the serum protein. The extent of such humoral reaction by the hosts was semiquantitated by the simple in vitro agglutination method. Cancer 40:693–699, 1977.