Antiepidermal growth factor variant III scFv fragment: effect of radioiodination method on tumor targeting and normal tissue clearance

As seen previously with the anti-EGFRvIII IgG mAb, retention of radioiodine activity in U87MGΔEGFR cells in the internalization assay was labeling method dependent, with SGMIB and SIPMB yielding the most prolonged retention. However, unlike the case with the intact mAb, the results of the internalization assays were not predictive of in vivo tumor localization capacity of the labeled scFv. Renal activity was dependent on the nature of the labeling method. With MR1-1 labeled using SIPMB, kidney uptake was highest and most prolonged; catabolism studies indicated that this uptake primarily was in the form of ϵ-N-3-[*I]iodo-4-phosphonomethylbenzoyl lysine.