Jurgen Conrad

The demonstration of human tumors on nude mice using gadolinium-labelled monoclonal antibodies for magnetic resonance imaging.

&NA; Göhr‐Rosenthal S, Schmitt‐Willich H, Ebert W, Conrad J. The demonstration of human tumors on nude mice using gadolinium‐labelled monoclonal antibodies for magnetic resonance imaging. Invest Radiol 1993;28:789‐795. rational and objectives. The authors describe the magnetic resonance imaging (MRI) of a tumor in a nude mouse tumor model by means of an antibody‐polylysine (Gd‐DTPA) conjugate. methods. The monoclonal antibody, (MAB) RA96, was coupled to a polymeric gadolinium complex after periodate oxidation. This polymer, which consists of a polylysine backbone and complexing DTPA subunits, complexes an average of 65 gadolinium ions. results. The immunoreactivity of the conjugates was reduced by an average of only 30% compared with the unbound MAB RA96. Biodistribution studies in nude mice with subcutaneously implanted human colon carcinomas (WiDr [specific] and HT29 [control]) revealed a tissue concentration in the specific tumor of 8.72% of the dose applied per gram despite the high molecular weight of the conjugates. conclusions. This tissue concentration is sufficient to achieve tumor‐specific signal enhancement in the WiDr tumor on MRI. The problem of the high doses of protein required for MRI and possible solutions are discussed.