Acid-treated, heated serum derivative for culture media for Leptospira

Genus-specific leptospiral antigen and its possible use in laboratory diagnosis

Sheep red cells, sensitized with a genus-specific leptospiral substance extracted from a water leptospira, were preserved by freeze drying. The serological reactivity of the preparation was tested against a total of 41 sera from proven cases of human leptospirosis and 27 from proven cases of animal leptospirosis. The sensitized, freeze-dried red cells appeared to be a sensitive reagent for the detection of leptospiral antibodies by haemagglutination. The use of this reagent as a screening test for leptospiral diagnosis is discussed. In the reported haemagglutination test on human and rabbit antisera the findings suggested that only IgM (19S) antibodies took part in the reaction.

Electron-microscopic evidence for reactions of axial filaments of Leptospira with IgM and IgG antibodies

Serological identifications of structural components of leptospires have not previously been reported although morphological and antigenic studies have been carried out extensively.The antigenic activity of isolated axial filaments was characterized by direct electron-microscopic visualization of immune precipitates with fractionated antisera. The precipitates were composed of axial filament with IgM or IgG antibodies attached.The axial filament is the first structural component of leptospires to be identified serologically. Knowledge of the pattern of cross-reactivity of this axial filament antigen among various serotypes may be of value in helping to establish a new system of classification based on specific antigens rather than the current system using reciprocal agglutinin-absorption tests, which measures the resultant of many antigens.