Hep88 mAbs, a novel monoclonal antibodies against hepatocellular carcinoma cell line from Thai patient, has been proved earlier for its tumoricidal effect on HepG2 cell line. In the present study, we investigated not only Hep88 mAb’s targeted proteins from HepG2 cell line by western blot analysis but also its inhibitory activity on those cells by MTT assay. Moreover, the ultrastructural alteration induced by Hep88 mAb of HepG2 cell line compare with Chang liver cell line was also examined. The results demonstrated that Hep88 mAb had cytotoxic effect on HepG2 cell line but not Chang liver cell line. Additionally, recognizing proteins against Hep88 mAb have been found on both cell lines. The ultrastructural alteration detected from transmission electron microscopy included the appearing of intracellular vacuolization as well as the dilatation of endoplasmic reticulum and mitochondria have been observed. These findings are suggested that the death of HepG2 cell line after treatment with Hep88 mAb might be involved by an apoptosis-like program cell death (PCD) pathway. From all of these remarks, it is possible that Hep88 mAb can injure HCC cells by binding with its membrane-bound antigen and activated downstream intracellular signals which is finally leading cell to be death via apoptosis-like PCD.

Keywords: Hepatocellular carcinoma, Monoclonal antibody, Cell cytotoxicity, Apoptosis, Transmission electron microscopy