Standardization and stabilization of an extract from Leptospira biflexa and its use in the hemolytic test for leptospirosis.

Abstract

A previous report from this laboratory (Cox, 1955) described a hemolytic reaction (HL) which involved the ability of leptospiral extracts to sensitize sheep erythrocytes to hemolysis in the presence of leptospiral antiserum and complement. These extracts were similar in preparation to those previously described by Chang and McComb (1954), who described their use in a hemagglutination test. The HL procedure was shown to be broadly specific, in sharp contrast to the high degree of type specificity seen in the conventional agglutination test. In comparison with the HL procedure, the hemagglutination test of Chang and McComb (1954) was found to be broadly specific but considerably less sensitive, a finding subsequently confirmed by Chang, et al (1957). Although the HL reaction as first reported satisfied the demand for a serodiagnostic test which was broadly specific and safe in operation, the procedure for preparation of the HL extract was hazardous in that it was prepared from cultures of Leptospira pomona. Furthermore, the HL reaction as described in the first report was not simplified with respect to standardization of reagents for performance as a routine procedure. Subsequent studies in this labora-