Pancreatic fate of a I-125-labelled mouse monoclonal antibody directed against pancreatic B-cell surface ganglioside(s) in control and diabetic rats

The possible use of a mouse monoclonal antibody directed against rat pancre atic B-cell surface ganglioside(s) and labelled with radioactive iodine for selective imaging of the endocrine pancreas by a non-invasive procedure wa s investigated by following its pancreatic fate in experiments conducted ei ther in vitro by incubation of rat isolated pancreatic islets, acinar tissu e and pancreatic pieces or in vivo after intravenous injection of the I-125 -labelled antibodies ([I-125]gamma -G). Although the binding of [I-125]gamm a -G per mug protein was about one order of magnitude higher in isolated is lets than in acinar tissue, no significant difference was detected when com paring pancreatic pieces or isolated islets from control animals and rats r endered diabetic by one or two prior administrations of streptozotocin (STZ rats). Likewise, except in one set of experiments, no significant differen ce was found between control animals and STZ rats, when measuring the radio active content of the pancreatic gland, relative to that of plasma, 1-4 day s after the intravenous injection of [I-125]gamma -G. These findings indica te that under the present experimental conditions, the mouse monoclonal ant ibody labelled with radioactive iodine does not appear to be a promising to ol for selective imaging of the endocrine pancreas, e.g. by single photon e mission computerized tomography. Copyright (C) 2000 John Wiley & Sons, Ltd.