Monoclonal Antibody to Rat Plasma Kallikrein

Monoclonal antibody (MAb) was obtained to rat plasma kallikrein after immunization of BALB/c mice with the purified enzyme. Spleen cells from immunized mice were fused to P-3 mouse myeloma cells. Four antibody secreting hybridomas were identified by enzymelinked immunosorbant assay (ELISA) for production of antibody to rat plasma kallikrein. One hybrid was cloned by limiting dilution and expanded as ascites tumor by injection of 5 X 106 cells into the peritoneal cavity of male BALB/c mice primed with 2,6,10,14-tetramethylpentadecane. Antibodies at a dilution as great as 1:20,000 were detected in ascites fluid and sera of immunized animals. The lower limit of detection of kallikrein was 0.1 μg/ml. Secreted antibodies bound specifically to rat and human plasma kallikrein, but did not show any immunological interaction with human urinary or porcine pancreatic kallikrein. The MAb provides the necessary component for an enzyme-linked plasma kallikrein immunoassay.