[Comparative study of outer envelope protein and LPS of five strains of leptospires by SDS-PAGE and 2D-PAGE]

We applied SDS-PAGE, 2D-PAGE and Western blot to analyse the outer envelopes protein and LPS of five strains of leptospires. The work would lay foundations for taxonomy, the development of vaccination regimens and the elucidation of pathogenic mechanisms. The outer envelope proteins of leptospires were analyzed by SDS-PAGE and silver staining. We found that the protein profiles of the pathogenic leptospires were basically identical. A comparison of the protein profiles of the pathogenic L. with those exhibited by two nonpathogenic L. indicated that there was no obvious relationship between these organisms and any of the L. interrogans strains examined. The quantity of 21.5 kd protein of strain 017 was greater than that of strain 601 and 156. Approximately 200, 225, 238 distinct polypeptides were detected in the strain 017, 601 and 156 in 2D-PAGE by silver staining respectively. The profiles of 2D-PAGe showed obvious differences in pI. The pI of strain 017, 601 and 156 were mainly 6.68-7.4, 6.55-6.9, 5.85-7.1 respectively. The 21.5 kd protein of strain 017 was made up of six polypeptides. Our immunoblots revealed that McAb (LB1) reacted with a 41 kd antigen, which was common to the three virulent leptospires tested. SDS-PAGE profiles of silver stained outer envelope LPS of pathogenic L. differed greatly from those of the nonpathogenic L. There was a distinct differences between strain Patoc I and 3055. Our studies showed that each of the five strains of leptospires possessed characteristic outer envelope LPS, which may be used to identify the genus, species and serovars of a strain of L.