2DE immunoblotting analyses of P97 adhesin. Proteins samples from the M. hyopneumoniae strains J (C), 7448 (B), and 7422 (A) were resolved by 2DE as described in Figures 1 and 2, electroblotted onto PVDF membranes, and probed with the anti-P97 monoclonal antibody F1B6 (1:400 dilution). Anti-mouse IgG alkaline phosphatase-labelled secondary antibody (1:2000 dilution) was used to develop antigen-antibody reactions. The approximate molecular weights are shown on the left of the gel and the acid-to-alkaline gradient is from left to right. Mature P97 (P97), its two main proteolytic products (a and b), and the P97 pathogenic-strain-specific, low-MW proteolytic products (1-4) are indicated.