Characterization of Mycobacterium paratuberculosis and "wood-pigeon" mycobacteria by isoenzyme profile and selective staining of immunoprecipitates.

Cell-free extracts of various strains belonging to Mycobacterium paratuberculosis (Ptb) and "wood-pigeon" (WP) mycobacteria were compared by polyacrylamide gel electrophoresis and the various protein bands obtained were tested for peroxidase enzyme activity. One strain of Mycobacterium avium served as a control. Bacterial extracts were also analysed by crossed immunoelectrophoresis (CRIEP) and fused rocket immunoelectrophoresis (FRIEP) using antisera raised in rabbit against M. paratuberculosis and WP mycobacteria. The immunoprecipitates obtained both in CRIEP and FRIEP plates were subsequently stained for selective peroxidase enzyme staining. Our results showed that, although Ptb and WP mycobacteria shared common peroxidase isoenzymes and antigens, they also had specific immunoprecipitates showing the differences between the two groups of bacteria.