Klebsiella pneumoniae haemolysin adsorption to red blood cells.

It was necessary to incubate the Klebsiella pneumoniae haemolysin with erythrocytes at 37 degrees C to produce the whole lytic action. The amount of attached klebolysin at 4 degrees C increased as its concentration in the medium increased, until the erythrocyte surface was saturated. Treatment with 2-mercaptoethanol was necessary to permit the adsorption; it was inhibited by low concentrations of cholesterol. Klebsolysin was immunogenic and its antiserum neutralized its own haemolytic effect and streptolysin O. Anti-streptolysin serum also neutralized klebsolysin. Streptolysin O attachment to erythrocytes impeded the posterior klebolysin adsorption in the same way that klebsolysin adsorption interfered with streptolysin O attachment.