Further Characterization of Monoclonal Antibodies against Rat Plasma Kallikrein, Rat Low Molecular Weight Kininogen and Synthetic Bradykinin

Abstract

Monoclonal antibodies (MAbs) to rat plasma kallikrein, rat plasma low molecular weight kininogen and synthetic bradykinin were characterized further. The MAbs were obtained after the immunization of BALB/c mice with the purified reagents and synthetic bradykinin coupled to ovalbumin. The MAbs were very useful in characterizing components of the kallikrein-kininogen-kinin system. Plasma kallikrein MAbs bound specifically to both rat and human plasma kallikrein but did not interact immunologically with either rat or human glandular kallikrein. The MAbs immunoprecipitated about 75% of the kallikrein enzyme activity. Five stable hybridomas were obtained that produced MAbs against bradykinin. These MAbs cross-reacted with bradykinin, bradykinin analogues, purified rat plasma kininogen and tryptic digests of rat plasma kininogen. The MAbs also neutralized the smooth muscle contractile activity of bradykinin. The specificity of MAbs against rat plasma kininogens was confirmed by immuno-precipitation of 125I-kininogen with MAbs followed by SDS-PAGE. These MAbs were used successfully to develop immunoassays (ELISA) and immunoadsorbents to purify components of the kallikrein-kininogen-kinin system.