Protein and antigen profiles of prevalent serovars of Leptospira interrogans.

Whole-cell and detergent-soluble proteins, enriched for outer membrane antigens, of the Leptospira interrogans serovars present in commercially available pentavalent vaccines (hardjo, pomona, icterohaemorrhagiae, grippotyphosa, and canicola) were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting (immunoblotting). Protein and antigenic profiles of these serovars, representing several serogroups, were compared with similar profiles of the most common North American bovine pathogen, serovar hardjo type hardjo bovis. The reference strain of serovar balcanica and a hardjoprajitno bovine field isolate (serovar hardjo) were also assayed. Coomassie blue-stained gels revealed extensive protein similarities, and Western blots demonstrated antigenic relatedness throughout the low- and high-molecular-weight regions. Possible quantitative differences in protein expression among the strains were noted, as were similarities in the protein profiles of type hardjo bovis and the balcanica reference strain. A cocktail composed of these homologous antigens may serve as an efficacious subunit vaccine for leptospirosis.