Immunohistological characterization of human monoclonal antibody against lung cancer.

Using immunoperoxidase staining method, a human monoclonal antibody (MAb), termed HB4C5, which was generated by fusion of NAT-30 cells with regional lymph node lymphocytes from a lung cancer patient, was examined for tumor specificity. The determinant recognized by HB4C5 MAb was well preserved in usual formalin-fixed paraffin-embedded tissue sections. Experiments with four major histological types of the lung cancer showed that HB4C5 MAb reacted with adenocarcinoma (19/27), squamous cell carcinoma (2/15), and large cell carcinoma (4/6), but not with small cell carcinoma (0/7). The immunoreaction was seen in the cytoplasm. In addition, this MAb also reacted with some gastric and colon adenocarcinomas. Further study on normal lung and nonpulmonary tissues revealed that HB4C5 MAb bound only type II pneumocytes and proximal tubules of normal kidney.