Establishment of OVS3 monoclonal antibody recognizing human ovarian cancer.

ABSTRACT

OVS3 monoclonal antibody (MAb) was established by fusing murine myeloma cell line NS 1/1-Ag 4-1 with spleen cells from mouse immunized with fresh ovarian endometrioid carcinoma. The MAb was selected by a specific immunohistological (streptavidin-biotin) staining on the tumor area of frozen sections of the same tumor. The immunohistological staining with OVS3 MAb was also screened on frozen sections of 21 normal tissues, 5 benign tumors, 20 ovarian cancers and 5 other cancers. The positive result was 50% in all ovarian cancers compared to almost negative results in the other groups (97% specificity). The heat labile property of OVS3 antigen (Ag) was found when hegative staining results were shown in all paraffin sections in spite of positive reactions on frozen sections of the same tumors. The OVS3 Ag was confirmed to be a 3-subunit protein of 40-50 kD molecular weight by the immunoprecipitation technique. The data supported OVS3 MAb as another new MAb recognizing an epitope different from the previously established OVS1 and OVS2 MAbs.