Detection of specific anti-leptospiral immunoglobulins M and G in human serum by solid-phase enzyme-linked immunosorbent assay

Analysis of Leptospira antigens by crossed immunoelectrophoresis

Serovars icterohaemorrhagiae, canicola, and arboreae of pathogenic Leptospira interrogans and serovar patoc of saprophytic L. biflexa were examined by crossed immunoelectrophoresis. A close antigenic relationship was found between the interrogans serovars, particularly between icterohaemorrhagiae and canicola. To a much lesser extent cross-reactions were found between interrogans serovars and patoc. Comparison of three different antigenic preparations of icterohaemorrhagiae by tandem crossed immunoelectrophoresis and by absorption experiments with the patoc reference system showed the presence of several common broadly reactive antigens. Antigen 1 of the reference system, a genus-specific heat-stable protein antigen, was found in all antigenic preparations. It is a diagnostically important antigen.

A pomona serogroup-specific, agglutinating antigen in Leptospira, identified by monoclonal antibodies

Monoclonal antibodies were produced by hybridoma cell lines derived by fusion of mouse NS-1 myeloma cells with splenocytes from mice immunized with Leptospira interrogans serovar pomona. One hybridoma (A3) produced an IgG2a antibody which agglutinated all leptospires of the Pomona serogroup but not leptospires representative of serovars of any other serogroup. The antibody precipitated in immunodiffusions with either alkali- or phenol-extracted lipopolysaccharide and also with the TM antigen of Yanagawa et al., indicating a common determinant on both antigens. A3 antibody opsonized viable leptospires for phagocytosis by mouse macrophages in vitro.

Bovine IgM and IgG response to Leptospira interrogans serovar hardjo as measured by enzyme immunoassay

The enzyme-linked immunosorbent assay (ELISA) was used to detect specific IgG and IgG antibodies in the sera of cattle infected or immunized with Leptospira interrogans serovar hardjo. IgM appeared first but was quickly followed by IgG which persisted longer than IgM. The levels of antibody detectable by ELISA and by the microscopic agglutination test (MAT) did not correlate, suggesting that the two techniques measured different antigen--antibody systems. The transient nature of the IgM response as measured by ELISA indicates potential usefulness as a serodiagnostic test for detecting current leptospiral infections.

The enzyme-linked immunosorbent assay (ELISA) as a serological test for detecting antibodies against Leptospira interrogans serovar hardjo in sheep

The enzyme-liked immunosorbent assay (ELISA) was compared with the standard microscopic agglutination test (MAT) as a method for detecting antibodies against Leptospira interrogans serovar hardjo in sheep. Peak antibody levels detected by the 2 tests occurred at different times following experimental infection of sheep. In serums from flocks of sheep with naturally acquired infection there was a 95% correlation between MAT and ELISA with respect to the presence or absence of antibody to serovar hardjo, although the levels of correlation of the titres of the 2 tests was low. The 2 tests appeared to measure different antigen-antibody systems. The ELISA would be a useful test for screening large numbers of serums for antibodies to L. interrogans serovar hardjo.