Monoclonal Antibodies against Non Specific Cross-Reacting Antigen

Abstract

Publisher Summary This chapter discusses the mechanism of action of monoclonal antibodies against nonspecific cross-reacting antigens (NCA). The NCA is a component present in normal and cancer tissues able to cross-react with the well-known carcinoembryonic antigen (CEA). The NCA is a glycoprotein, with a molecular weight of around 60,000 Daltons and a β electrophoretic mobility. It has its own antigenic determinants shown by the fact that anti-NCA sera absorbed by CEA continue to precipitate. Some experiments were performed to know if epitopes found on NCA were on protein or polyssaccharidic moieties. NCA and tissular extracts were submitted to enzymatic digestion with neuraminidase and to chemical treatment with periodate. The three monoclonal antibodies were used to detect NCA on tissue sections. Some monoclonal antibodies that seemed to be useful in RIA or EIA did not detect NCA on tissues sections. This effect could be due either to fixation damage or to steric hindrance of the antigenic molecule, or more probably to a relatively weak affinity of the negative antibodies.