Immunocytochemical identification of monoclonal antibodies with binding activity to acinar cells but not islets.

The development of techniques for separating islets from acinar cells on a mass scale is a prerequisite to successful clinical attempts at islet transplantation. We have identified and partially characterized two blood group-reactive monoclonal antibodies (McAb), CAC1 and CAC2, with specific binding activity to acinar cells but not islets. These McAb are of the IgM subclass, and were found on immunocytochemical analysis to possess broad interspecies cross-reactivity, binding to antigens expressed in the acinar tissue of rats, dogs, and man. The antigens that these McAb recognize are glycolipid in nature and thus were not denatured by collagenase digestion of the pancreas. These properties, together with their ability to effect complement-mediated lysis, may make the McAb generally useful reagents in islet isolation and purification.