Antileptospiral Activity of Serum I. Normal and Immune Serum

Johnson, Russell C. (University of Minnesota, Minneapolis), and Louis H. Muschel . Antileptospiral activity of serum. I. Normal and immune serum. J. Bacteriol. 91: 1403–1409. 1966.—Normal serum was found to exert a leptospiricidal effect, mediated by the complement system, against the nonpathogenic leptospires. Although resistant to normal serum, the pathogenic serotypes were susceptible to antiserum plus complement. Several variables in these immune leptospiricidal reactions were investigated. A reaction period of 3 hr at 37 C between serum substances and 1-day-old cells provided a maximal leptospiricidal effect. The normal serum of the rabbit, guinea pig, bovine, and human were leptospiricidal against the nonpathogenic serotypes, and, in conjunction with rabbit antiserum, rabbit and bovine complement were leptospiricidal against the pathogenic serotypes. Studies with C 14 -labeled leptospires indicated that the immune leptospiricidal reaction was associated with a loss of permeability control. Thus, like the gram-negative bacteria, the treponemes, erythrocytes, and nucleated mammalian cells, the leptospires may be included as cell types susceptible to the antibody-complement system.