Agglutination of murine tumor cells by sera from patients with autoimmune diseases.

Abstract

A method of <i>in vitro</i> agglutination of murine ascitic tumor cells which had been used to detect and to semiquantitate components with saccharide-binding properties in sera from cancer patients was applied on sera from patients with various autoimmune diseases. Sera from 36 of 56 patients with such diseases, after removal of their cytocidal activity on the murine tumor cells by absorption with liver tissue from normal adult mice, agglutinated the tumor cells which had been harvested while they were rapidly proliferating <i>in vivo</i>. The agglutination activity was absorbed completely by embryonic tissue of mouse. The agglutination was inhibited by perchloric acid extract of the tumor cells and also by monosaccharides such as galactose or <i>N</i>-acetyl-<i>D</i>-glucosamine. The inhibition activity of the perchloric acid extract was affected by treatment with glycosidases but not trypsinization. These results showed that carbohydrate moieties of murine tumor cell surface components were involved in the agglutination and therefore that there was an increase of components with saccharide-binding properties in the sera of patients with autoimmune diseases compared to the sera of normal controls. This increase in turn suggested by analogy to tumor-bearing animals that a sort of humoral reaction took place in the patients against changes related to autoimmune diseases of carbohydrate moieties of the cell surface substances.