Immunocytochemical detection of lung cancer cells with monoclonal antibodies to 14-3-3 proteins.

Murine monoclonal antibodies were raised against 14-3-3 proteins, the antigen of human monoclonal antibody AE6F4 which had been shown potentially useful for the immunochemical diagnosis of lung cancer via sputum cytology. Enzyme-linked immunosorbent assays of the murine anti-14-3-3 monoclonal antibodies with isolated bovine brain 14-3-3 isoforms showed that the antibodies were classified into four different profiles of isoform reactivity. The comparison of 14-3-3 isoform and lung cancer tissue on the reactivity with murine monoclonal antibodies indicated that beta isoform can be responsible for cancer recognition, whereas human monoclonal antibody AE6F4 showed preferential binding to zeta isoform. No murine monoclonal antibody of the same isoform specificity as human monoclonal antibody AE6F4 was obtained. Since murine monoclonal antibodies with different isoform specificities could immunostain lung cancer cells in sputum successfully, the combination use of murine monoclonal anti-14-3-3 antibodies with human monoclonal antibody AE6F4 is potentially useful for facilitating the sputum cytodiagnosis of lung cancer.