Development and characterization of monoclonal antibodies specific for two different exoproteases of Aeromonas salmonicida

Monoclonal antibodies (mabs) against native epitopes of Aeromonas salmonicida strain F216.1/83-secreted proteases were isolated by means of a Protease-Capture-Assay. Ten antibodies reacted with the 70-kDa serine protease as judged from the molecular mass and enzymatic behaviour of the recognized antigen. Eight other mabs bound gelatinolytic antigens which lacked caseinolytic properties and possessed some characteristics of a zinc-dependent metalloprotease. The molecular mass of these mab-defined, immunologically cross-reactive antigens were estimated to be predominantly 108, 90 and 57 kDa. By comparing the antigen recognition and epitope mapping profiles among anti-serine protease- and anti-metalloprotease-mabs, at least six and five different epitope specificities were demonstrated, respectively. Both panels of mabs were shown to recognize the two types of exoproteases in culture filtrates of strain MT004 and of several other typical A. salmonicida strains.