Development of new immunoradiometric assay for CA 125 antigen using two monoclonal antibodies produced by immunizing lung cancer cells.
CA 125 is an antigen associated with non-mucinous epithelial ovarian cancer, which is defined by OC 125 antibody developed by immunizing ovarian cancer cells. We have produced two monoclonal antibodies, 130-22 and 145-9, by using the human lung adenocarcinoma cell line PC-9. Both 130-22 and 145-9 antibodies recognized CA 125 antigen. However, the binding sites seemed to be separate from those of OC 125. Testing by 9 immunoradiometric assays (IRMA), using different combinations of the 3 monoclonal antibodies 130-22, 145-9 and OC 125 demonstrated that the best standard curve for detecting CA 125 could be obtained by a "simultaneous sandwich" assay based on a mixture of 125I-labeled OC 125 and 130-22 or 145-9 coated beads. One-step IRMA, using 130-22 as a tracer and 145-9 as an immunoadsorbent, also showed good reproducibility and sensitivity for measuring CA 125. Antigens were detectable in the culture supernatants of PC-9 cells and 5 of 6 ovarian cancer and endometrial adenocarcinoma cells. These results indicate that one-step IRMA using 130-22 and 145-9 is useful for detecting CA 125 antigen.
Kunimatsu
M
M
Department of Nuclear Medicine, Kyoto University Hospital, Japan.
Endo
K
K
Nakashima
T
T
Awaji
T
T
Saga
T
T
Watanabe
Y
Y
Kawamura
Y
Y
Ohta
H
H
Koizumi
M
M
Sakahara
H
H
D000230:Adenocarcinoma / Q000276:immunology; D000911:Antibodies, Monoclonal; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000032:analysis*; D005260:Female; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods*; D066298:In Vitro Techniques; D008175:Lung Neoplasms / Q000276:immunology; D010051:Ovarian Neoplasms / Q000276:immunology; D014594:Uterine Neoplasms / Q000276:immunology
D000911:Antibodies, Monoclonal; D015295:Antigens, Tumor-Associated, Carbohydrate