Comparison of Mycoplasma bovis strains based on SDS-PAGE and immunoblot protein patterns

Whole-cell protein patterns generated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were compared for 34 isolates of Mycoplasma bovis. A high degree of similarity between most of the strains was established with strain-to-strain differences mainly confined to quantitative variations of certain protein bands, particularly in the molecular weight regions of 64-68, 55 and 26 kD. Two of the isolates provided more deviating patterns. Hydrophobic membrane protein fractions of the strains as prepared by Triton X-114 phase partitioning were compared by SDS-PAGE, which confirmed some of the characteristic strain features found with whole-cell proteins. The immunoblot analysis revealed that up to 20 of the 50-55 discrete protein bands detected in SDS-PAGE patterns were recognized to be antigenic by rabbit and bovine hyperimmune sera. It is concluded that the same set of major antigens is present in all strains investigated, but amounts of individual constituents may be differing.