Objectives: To obtain F(ab')2 fragment of monoclonal antibody (McAb) COC166-9 and to perform its radioimmunoimaging (RII) for ovarian carcinoma.
Methods: McAb COC166-9 was digested into F(ab')2 by ficin and tested by SDS-PAGE. After purification by DEAE-32, F(ab')2, COC166-9 and normal murine IgG (nMIgG) were labelled by 131I and injected intraperitoneally into three groups of nude mice bearing human ovarian cancer xenografts respectively. 72 hours after injection, RII was performed in three groups of mice.
Results: The yield of F(ab')2 was 54%, about 80% of the maximal theoretical yield. Good immunoreactivity of F(ab')2 retained with higher ratio of tumor to normal tissue radioactivity (T/NT) than that of intact COC166-9. RII showed better result with lower nonspecific background than the latter.
Conclusion: F(ab')2 could be obtained by ficin digestion with good yield and immunoactivity as well as better RII than intact monoclonal antibody.