Molecular comparison of antigens and proteins of virulent and avirulent clones of leptospira interrogans serovar copenhageni, strain Shibaura

The antigens and the protein profiles of virulent and avirulent clones of Leptospira interrogans serovar copenhageni, strain Shibaura were compared by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting and radioimmunoprecipitation. An antigen specific to the virulent clone was detectable only in the virulent clone by Western blotting using anti-virulent clone but not anti-avirulent clone antisera. The molecular weight of the antigen was estimated to be approximately 32000 by SDS-PAGE, and the antigen was found to be thermostable. A 43000 dalton antigenic molecule was found to be specific for the virulent clone, and the 41000 dalton antigenic molecule was found to be specific for the avirulent clone by Western blotting using both anti-virulent and anti-avirulent clones antisera. Therefore, these antigenic molecules seemed to contain at least one antigenic determinant which is common to the virulent and the avirulent clones. No difference between the virulent and avirulent clones was observed in the comparison of protein profiles on SDS-PAGE and surface exposed antigenic protein profiles on radioimmunoprecipitation using radioiodinated leptospiral surface exposed proteins. Therefore, the antigens which were different between the virulent and avirulent clones were suspected not to be protein antigens.