A new murine monoclonal antibody against human hepatoma

Preparation and identification of monoclonal antibody against human hepatocellular carcinoma with a novel immunization

The purpose of this study was to prepare and identify a novel monoclonal antibody (MAb) against human primary hepatocellular carcinoma (PHC) with high specificity and activity. The hepatocellular carcinoma cell line HepG2 was used to immunize BALB/c mice for preparing MAb with the classic hybridoma production technique. Tail vein injection immunization combined with intrasplenic injection was applied for improvement. Immunoperoxidase staining studies showed that the MAb was reactive to HepG2 and another hepatocellular carcinoma cell line, SMMC7721, 98.5% (67/68) specimens of hepatocellular carcinoma, but not to normal human liver tissues and tissues derived from the other malignant tumors, except one of the five specimens of cholangiocarcinoma with dubious staining. Laser confocal scanning microscope (LCSM) analysis indicated that the MAb reacted with the whole cell, including the membrane fractions and the cytoplasm. The hybridoma cell contained 103 +/- 5 chromosomes, and the MAb was identified as IgM subclass by ELISA. It was concluded that this combined immunization can effectively produce highly specific MAb against PHC, and this MAb may be of potential use as a targeting agent for radionuclide therapy and chemotherapy for hepatocellular carcinoma.

Novel tumor-associated antigen of hepatocellular carcinoma defined by monoclonal antibody E4-65

A monoclonal antibody, E4-65, produced by immunizing mice with SMMC-7721 cells, a human hepatocellular carcinoma (HCC) cell line, was used to identify and characterize an unreported HCC-associated antigen. Indirect immunofluorescence studies showed that E4-65 antibody reacted with five out of eight HCC cell lines, but not with 10 non-HCC tumor cell lines or a normal liver cell line. Using immunohistochemical examination, E4-65 antigen was detected on the cell membranes and in the cytoplasm of human liver tumor tissues, but was not found in most other tumors, or normal adult or fetal tissues, except for a weakly positive reaction in tissues of the digestive system. Western blot analysis showed that E4-65 antibody bound to a 45 kDa protein in the human HCC cell line and tissue lysates. Enzyme treatment and lectin blotting did not detect the carbohydrate chain in E4-65 antigen. This HCC-associated protein represents a potentially useful target for diagnoses and immunotherapy of human HCC.