Human hepatocellular carcinoma: Cross-reactive and idiotypic antigens associated with malignant transformation of epithelial cells

✍ Scribed by Karl H. Wiedmann; Ludwik K. Trejdosiewicz; Jennifer Southgate; Howard C. Thomas

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 973 KB
• Volume: 7
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.1840070321

✦ Synopsis

e d s LS9 7TF. England Monoclonal antibodies were isolated following immunization with the HBsAg and a-fetoprotein-secreting human hepatoma PLC/PRF/5 ("Alexander") cell line. Three antibodies (K-PLC1, K-PLC2 and K-PLC3) showed evidence of carcinoma-associated reactivity by indirect immunofluorescence. Antibodies K-PLC2 and K-PLC3 reacted only with PLC/PRF/5 cells, but not with any other normal or malignant cell type tested, including the HeplC2 hepatoma cell line. The reactivity of these antibodies was not removed by absorption with homogenates of either normal liver or a primary hepatocellular carcinoma. These results suggest that K-PLC2 and K-PLC3 identify PLC/PRF/S idiospecific determinants. Following surface iodination of PLC/PRF/5 cells, immunoprecipitation and analysis on polyacrylamide gels, these specific determinants were found to be of 200,000 and 76,000 daltons, respectively. On the other hand, antibody K-PLC 1, although unreactive by immunofluorescence on the majority of normal cell types, including those of lymphoid organs and bone marrow liver cells and most epithelia, was weakly positive on some normal ductal secretory epithelia and was positive on vascular endothelium. However, K-PLC1 reacted strongly with all carcinoma specimens tested, and with most carcinoma-derived cell lines, indicating a large increase in K-PLC1 antigen expression by epithelial cells after malignant transformation. Absorption of K-PLCl with normal liver homogenate had no affect, but absorption with a hepatocarcinoma homogenate abolished its activity. The K-PLCl antigen could not be immunoblotted or immunoprecipitated and resolved on polyacrylamide gels; yet it showed the properties of a phospholipid, namely resistance to proteases, extractability with organic solvents and sensitivity to phospholipase C.

Primary liver cell cancer (PLCC), one of the most common tumors in man with a particularly high inci-