Human monoclonal antibody 28K29 highly reactive with lung adenocarcinomas of all grades of differentiation and with large cell carcinomas

Human monoclonal antibody (mAb) 28K29 was previously established by fusing regional lymphocytes from a lung adenocarcinoma patient with human-mouse he teromyeloma. This mAb was shown to have an antigen localized in the membran e and cytoplasm of lung cancer cells. This mAb was investigated for reactio n with tissue sections from formalin-fixed paraffin-embedded blocks from 10 0 patients with lung cancer. The mAb 28K29 reacted with 83% (5/6) of the we ll-differentiated, 79% (22/28) of the moderately-differentiated, and 67% (4 /6) of the poorly-differentiated lung adenocarcinoma sections. The mAb also reacted with 35% (14/40) of the squamous cell carcinoma sections, 70% (7/1 0) of the large cell carcinoma sections, and 20% (2/10) of the small cell c arcinoma sections. In Western blot analyses, a broad band at a molecular we ight of approximately 600 kDa was detected in extracts from the lung cancer tissues positive for immunohistostaining with the mAb 28K29. The results o f the study suggest that the expression of the 28K29 antigen is independent of the histological differentiation grade in lung adenocarcinoma and that this antigen might be a useful marker for detection of both Barge cell carc inoma and adenocarcinoma of the lung as well as for investigation of the pu tative transition of large cell carcinoma to adenocarcinoma proposed by Yes ner. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.