[Reactivity of monoclonal antibodies ALT-01 and ALT-04 and identification of lung cancer-associated antigens].

ABSTRACT

Two IgG1 type monoclonal antibodies ALT-01 and ALT-04 were prepared by two different immunization schedules. ALT-01 was generated by fusing murine myeloma NS-1 cells with splenocytes from a BALB/c mouse immunized by human lung squamous carcinoma cells, which were coated by antisera to mixed human lymphocytes. For preparation of ALT-04, human lung squamous carcinoma xenograft-bearing nude mice were injected I. P. with the spleen cells of normal BALB/c mice in order to acquire immunofunction. The spleen cells from these tumor-bearing nude mice were fused with NS-1 cells. Then, these hybridomas were screened and cloned for 3 times. Two antibodies were shown to recognize the surface antigen on human lung carcinoma cells and several kinds of tumor cell lines but not those on normal cell lines. ALT-01 reacted to neither human lung carcinoma tissue nor its xenograft. ALT-04 reacted to human lung carcinoma tissue, of which, reaction to adenocarcinoma was the strongest but not to various normal tissues. Immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis and autoradiography was used to detect the associated antigen in 35S-labeled human lung carcinoma cells. Antigens, reacting to ALT-01, show one band of Mr 38,000 but those to ALT-04 reveal two bands of Mr 48,000 and 36,000.