Search

Antigenic recognition of leptospiral antigens by vaccinated or infected dogs was studied by microagglutination test (MAT) and by western blots. In western blots, serovar specific antigens detected by MAT migrated in the 18-31 kDa zone. The 25-31 zone seemed to be linked to antigens indicating virulence of the strain. These antigens are LPS. The first antibodies made after infection are produced against LPS migrating in the 14 kDa zone. Many protein antigens are common in leptospires belonging to different serogroups. Virulent strains exhibited specific antigens in the 45 and 32-34 kDa zones.

Seven strains of Leptospira interrogans belonging to seven different serogroups, and one strain of Leptospira biflexa were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with gradient gels and immunoblotting with hyperimmune rabbit sera raised against each strain. The molecular masses of the proteins were calculated with a polynomial regression model. The SDS-PAGE patterns of the L. interrogans strains were similar and characterized by 24 common bands. This profile was not found for L. biflexa. The immunoblots obtained either with the seven anti-L. interrogans sera or the anti-L. biflexa serum allowed a clear distinction between the two species. Taken as a whole, the L. interrogans strain patterns revealed by the seven anti-L. interrogans sera were similar, sharing eight common major bands. A serovar- or serogroup-specific antigenic zone, ranging from 21 to 26 kDa, was also identified.