A tumour cell aggregation promoting substance from rat ascites hepatoma cells.

A substance capable of promoting tumour cell aggregation was released from rat ascites hepatoma cell (possibly from the cell surface) kept in Hanks' balanced salt solution (free of calcium and magnesium) in the cold, and then partially purified by chromatography with DEAE-Sephadex and gel filtration with Bio-gel. The thermostable substance seemed to be a glycoprotein and its molecular weight was about 72,000 when measured by gel filtration on Sephadex G-200. It had no proteolytic activity. The material was clearly effective for rat ascites hepatoma cells as well as SV40 transformed cells, but less effective for Chang's cells and apparently ineffective for normal rat liver cells and red blood cells. The action of this material was more potent than that of Jack bean concanavalin A when assayed for aggregation of SV40 transformed cells. Its effect was not influenced by concanavalin A inhibitors such as alpha-methyl-D-glucopyranoside, N-acetyl-D-glucosamine and D-glucose.