Radioimmunodetection of a transplantable human bladder carcinoma in a nude mouse.

The results of an in vitro mixed hemadsorption (MHA) assay predicted the success of in vivo tumor localization using a radioiodinated, monoclonal, IgG1 antibody (A2) with reactivity to the human bladder carcinoma cell line RT4. In vitro, murine monoclonal antibodies A2 and G6, demonstrated reactivity to RT4 with titers of 1/1024 and 1/4 by MHA assay, respectively. In vivo results obtained with RT4 xenografts in athymic nude, Balb/c, mice indicated tumor uptakes of 1.10% dose/gram with A2 and 0.29% dose/gram with G6 at seven days after radiotracer injection. Successful scintigraphic imaging of tumor xenografts was achieved with A2 but not with G6 or radioiodinated mouse serum albumin.