Natural IgG antibody with anti-β-galactosyl specificity suppressed hepatoma cell invasion in culture

Abstract

The effect of natural IgG antibody recognizing b-galactosyl epitope on hepatoma cell invasion was investigated. Anti-b-galactosyl antibody dosedependently suppressed hepatoma invasion underneath primarily cultured mesothelial cells monolayer without affecting the proliferation, to the same extent as natural IgG antibody with anti-a-galactosyl specificity, which had already been reported to have an anti-metastatic activity. The inhibitory effect of anti-b-galactosyl antibody was completely canceled by adding lactose (galactose-b-1, 4-glucose) to the medium, indicating that this antibody recognized some antigens with bgalactosyl epitope. Hepatoma cells pretreated with this antibody for 48 h showed reduced invasive activity, while the pretreatment of mesothelial cells with the antibody did not affect hepatoma cells invasion. Anti-bgalactosyl antibody also suppressed hepatoma cells adhesion to mesothelial cells monolayer. These results suggest that natural antibody with anti-b-galactosyl specificity may recognize the b-galactosyl epitope in some adhesion-related molecules on hepatoma cells, thus suppressing adhesion and invasion to mesothelial cells monolayer. These results suggest possible therapeutic uses of this antibody in the treatment of metastatic tumors.