Identification of outer envelope proteins conserved among Leptospira serovars

Six serovars (hardjo hardjoprajitno reference strain, hardjo hardjobovisA s train, pomona, icterohaemorrhagiae, canicola, and grippotyphosa) of Leptosp ira interrogans were treated with Triton X-114 to identify common outer env elope proteins. Proteins that selectively extracted into the detergent phas e were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresi s (SDS-PAGE) and western blotting. Three major proteins of 32, 40, 45 kDa a nd another in minor quantity at 22 kDa, were common to all serovars. Antibo dies were prepared against pomona detergent phase proteins and were found t o recognize proteins of the same molecular weights on western blots contain ing whole cell lysates of all six serovars. Surface proteolysis, immunoprec ipitation and immunofluorescence were utilized to ascertain the location of these antigens. Results from these experiments indicate that the 32, 40, a nd 45 kDa proteins may be present on the outer surface of Leptospira. Evide nce demonstrating the outer surface location of these antigens suggests tha t they may be potentially useful as diagnostic reagents or as vaccine compo nents.