Monoclonal-antibody-defined human lung tumour cell-surface antigens

A panel of 3 monoclonal antibodies (MAbs) directed against human lung tumour cell-surface antigens has been produced following immunizations with the established small-cell lung cancer (SCLC) cell line, NCI-H69, and with another SCLC cell line, COR-L32, recently derived from clinical material. One MAb, B10/12, reacted strongly with SCLC, immunoprecipitated a protein having an MW of 100kd and failed to react significantly with non-small-cell lung cancer (NSCLC) in radioimmunoassay and in an immunohistochemical assay. MAbs E10/5 and 2G3 reacted extensively with SCLC but also showed significant reactivity with NSCLC. MAb E10/5 immunoprecipitated a protein with an MW of 80kd but no appreciable protein was specifically precipitated by MAb 2G3. Unlike MAb 2G3, both MAbs B10/12 and E10/5 reacted strongly with selected neuroblastomas whereas only MAbs 2G3 and E10/5 reacted significantly with melanoma. All 3 MAbs reacted with breast carcinomas. Other non-pulmonary tumours thus far examined failed to react with the MAbs in radioimmunoassay or immunohistochemical assay. Immunocytochemistry and the use of viable cells in radioimmunoassay confirmed that the antigenic determinants recognized by these MAbs were surface located.