Radioiodination of JAA-F11 via protected direct iodination for immunolocalization of breast cancer metastasis
Gharpure, Kshipra M.
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Breast cancer is the second most common cause of deaths after lung cancer. The major concern is the metastasis of breast cancer to other normal tissues. It is thus very important to detect metastasis at an early stage. Radioimmunolocalization with positron emission tomography is one of the methods for detection. Thomsen-Friendenreich (TF) antigen is a pancarcinoma antigen expressed in many types of tumors. JAA-F11 monoclonal antibody is highly specific for TF antigen. Previous attempts to label JAA-F11 with 124 I did not give very satisfactory results as JAA-F11 lost its reactivity after direct iodination. Hence it was decided to improve the method of direct iodination by protecting the binding sites of JAA-F11 with TF-Ag. Thus the hypothesis of this thesis is 'If JAA-F11 is saturated with TF-Ag during iodination; the tyrosines and histidines in the CDRs will be protected and improved labeling will be seen.' JAA-F11 was purified and analyzed for its purity. Inhibition EIAs were performed to determine the antigen which can protect JAA-F11 during iodination. Cold iodinations with Chloramine-T and iodobeads were done before hot iodination. Radiolabelling with 124 I was carried out using Chloramine-T method and PET images of a nude mouse injected with the labeled JAA-F11 were taken. The yield of the iodination was very low. Hence the labeled JAA-F11 did not localize to the tumor. For the future studies, other methods of radiolabelling such as metal chelator will be tried for labeling JAA-F11.