Characterization of monoclonal antibody 3G5 and utilization of this antibody to immobilize pancreatic islet cell gangliosides in a solid phase radioassay.

Monoclonal antibody 3G5, which was initially produced by immunization of mice with fetal rat brain, reacts specifically by indirect immunofluorescence with all cells of the pancreatic islets of human, rat, mouse, and bovine pancreas. This antibody reacts with the cell surface of isolated islet cells as well as the rat (RIN5F) insulinoma cell line. Antibody 3G5 reacts with islets, thyroid follicular cells, pituitary, and the adrenal medulla of a pattern similar to but distinct from those of antibody A2B5 and tetanus toxin, both of which react with complex gangliosides (sialic acid-containing glycosphingolipids). The antigen with which antibody 3G5 reacts also has the properties of ganglioside (neuraminidase sensitive, extracted into chloroform-methanol, partitioned into a methanol-water phase, soluble in water, and nondialyzable). Antibody 3G5, adsorbed to polyvinyl plates, can immobilize islet ganglioside micelles to which 125I-labeled 3G5, A2B5, and tetanus toxin all bind. The ability to immobilize micelles containing several complex gangliosides has led to a solid phase radioassay to detect antiganglioside antibodies. Monoclonal antibody 3G5 joins antibody A2B5 and tetanus toxin as markers for distinct complex gangliosides found on pancreatic islets and neurons.