Comparative analysis of lipopolysaccharide and lipid antigens of Leptospira interrogans serovars

Lipopolysaccharide (LPS) or glycolipid antigens of Leptospira interrogans have been candidates as serogroup or serotype specific antigen. In this study, therefore, we prepared the LPS and lipid antigens from L. interrogans serovars lai, icterohaemorrhagiae, copenhageni, canicola, pomona, grippotyphosa, and a Korean isolate 30R. The LPS antigens were analyzed by a polyacrylamide gel electrophoresis and lipid antigens by thin-layer chromatography, respectively. The seroreactivity of the antigens were also examined with homologous or heterologous antisera using an enzyme-linked immunosorbent assay. The LPS antigens from serovar lai and the strain 30R were closely related but different from serovar icterohaemorrhagiae. Particularly, the LPS antigens from serovars icterohaemorrhagiae and grippotyphosa were reactive only with the homologous antisera, thus indicating serovar specificity. However, the LPS antigens of the other serovars were reactive to the heterologous antisera. The lipid antigen of serovar icterohaemorrhagiae reacted only with the homologous antisera. In contrast, lipids of other serovars reacted broadly with heterologous antisera, particularly among serovars lai, copenhageni, canicola, pomona, and the strain 30R. The results thus indicated that the LPS and lipid antigens of L. interrogans may contain serovar-specific as well as cross-reactive epitopes.