[Binding of monoclonal antibodies to an insulin-producing rat tumor cell (RIN) after partial cell synchronization].

Murine monoclonal antibodies against pancreatic islet cell antigens were generated by somatic cell hybridization and their binding to the insulin-producing rat insulinoma cell line (RIN-5 AH) was evaluated in an indirect immunofluorescence test. An ascites dilution of 1:50 was used for immunostaining using RIN cells harvested from monolayer cultures in RPMI 1640 supplemented with 7.5% fetal calf serum (controls) or test cultures supplemented with 10 mmol/l hydroxyurea to collect the cells in G1/S phase. The five mc-ICSA tested showed a wide variety in their individual binding from 95 up to 30% but their binding was not influenced by hydroxyurea use for synchronization. The antigenic determinant recognized by the anti-glucolipid mc-ICSA 56a F3 was not present on all RIN-5 AH cells. In average, only 35% of the RIN cells showed a striking binding of the monoclonal 56a F3.