Complement-dependent cytotoxicity of monoclonal antibodies against islet cells

Mouse monoclonal antibodies producing cell lines were generated against rat and human islet cells by somatic cell hybridization using the mouse myeloma cell line P3-X63-Ag8. Four hybrid cell lines are growing as ascites bearing tumors. All four monoclonal antibodies reacted with cytoplasmic islet cell antigens as detected by the indirect immunofluorescence technique on Bouin-fixed pancreatic sections of Wistar rats. Besides their binding to cytoplasmic antigens three of them also recognized antigens expressed at the islet cell surface. Moreover, two of these three monoclonal antibodies were capable of mediating complement dependent cytotoxicity against rat islet cells as revealed in a 51Cr-release assay.