Bovine leptospirosis: The detection of haemolysin inhibitors in sera from experimentally and naturally infected cattle

Extract Strains of some serotypes of Leptospira produce, haemolysins with strong affinities for ruminant erythrocytes. The haemolysins are heat-labile, effective against erythrocytes after relatively long periods of incubation, and generally concentrated in extracellular culture fluids (Russell, 1956 Russell, C. M. 1956. A “haemolysin” associated with leptospirae. J. Immun., 79: 405–409. [Google Scholar]; Alexander et al., 1956 Alexander, A. D., Smith, O. H., Hiatt, C. W. and Gleiser, C. A. 1956. Presence of haemolysin in cultures of pathogenic leptospires. Proc. Soc. exp. Biol. Med., 91: 205–211. [Crossref], [PubMed] , [Google Scholar]; Valentine et al., 1964 Sullivan, N. D. 1970. Experimental infection of cattle with Leptospira hardjo. Aust. vet. J., 46: 121–122. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Russell (1956 Russell, C. M. 1956. A “haemolysin” associated with leptospirae. J. Immun., 79: 405–409. [Google Scholar]) reported that sera of rabbits immunized with a haemolysin producing strain of serotype pomona contained, in addition to agglutinins, inhibitors which neutralized the effects of the haemolysin. No corresponding studies in cattle appear to have been reported.