Effect of anti-cell and anti-axial filament sera on Leptospira.

Abstract

SummaryAntisera produced against either whole leptospiral cells or purified axial filament (AF) both possessed agglutinating activity towards live cultures and precipitated AF in gel diffusion reactions. The anti‐cell serum possessed, in addition, precipitating activity to an unideutified antigen when reacted against a crude preparation of AF.The AF antigen was heat‐labile; a suspension of boiled cells was used to absorb out antibodies to heat‐stable somatic antigens. This absorption resulted in a drop in the agglutinating titre in both the anti‐cell and anti‐AF sera, but residual agglutinating activity was always present after repeated absorptions. After absorptions, both of the antisera reacted only with AF antigen in precipitation with crude AF extracts.The anti‐cell sera showed immobilising activity which was apparently a secondary effect resulting from damage to the cell by anti‐somatic antibodies. The anti‐AF sera showed some, but not strong, immobilising activity. The absence of complete immobilisation dees not necessarily exclude the AF from a role in motility.Treatment with anti‐cell serum resulted in degradation of the leptospiral cell structure seen firstly in the enveloping sheath, followed by the protoplasmic cylinder and, finally, lysis. Treatment with specific anti‐AF serum did not lead to degradation or lysis of the cells.