Feasibility of Iodine-125 labeled anti-human hemoglobin antibody in the detection of bleeding sites from the large bowel - A preliminary study

A monoclonal anti-human hemoglobin antibody that crossreacts with mouse hem oglobin was labeled with Iodine-125 through the Chloramine-T method. The la beled antibody was used in an attempt to recognize bleeding sites from the large bowel in a mouse model, through a non-invasive enema-like study. In v itro experiments after double column chromatography of the labeled antibody and 10% trichloroacetic acid conjugation revealed that about 80% of the ra dioactivity was incorporated into protein. Inhibition assay containing cold (non-radiolabeled) antibody showed that Iodine-125 radiolabeled antibody p reserved its immunoreactivity. Autoradiographs exquisitely demonstrated acc umulation of isotope in the corresponding intestinal bleeding areas. These findings suggest that this method can be useful for scintigraphic localizat ion of bleeding sites in the large bowel.