title: Lysis of erythrocytes by a hemolysin produced by a group B Streptococcus sp.
abstract: An improved procedure for the isolation and purification of the hemolysin produced by a group B streptococcus was developed, and the inactivation of partially purified hemolysin by several enzymes was studied. Hemolysin obtained in buffer containing starch and Tween 80 was inactivated by subtilisin and alpha-amylase, suggesting that the hemolysin may consist of a protein hemolytic moiety complexed to starch which acts as a carrier or stabilizer. Properties of the hemolytic reaction were studied by using sheep erythrocytes as target cells. Experiments to examine the kinetics of hemolysis at different hemolysin concentrations resulted in a family of sigmoidal curves characterized by a short prelytic lag phase followed by a period of rapid release of hemoglobin. The binding of the group B hemolysin at 37 degrees C was rapid; within 3 min, most of the cells had bound sufficient hemolysin to produce lysis. In contrast, the hemolysin did not bind to erythrocytes at 0 degrees C. The length of the prelytic lag period and the rate of hemolysis were also temperature dependent. A decrease in total hemolysis was observed when the target cell/hemolysin ratio was increased, suggesting that a multihit response is required for lysis. Intracellular 86Rb and hemoglobin were released at the same rate from hemolysin-treated cells, indicating that a colloid-osmotic process is not involved in the lytic mechanism.
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability; D006460:Hemolysin Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D006461:Hemolysis; D007700:Kinetics; D010447:Peptide Hydrolases / Q000378:metabolism; D012413:Rubidium / Q000378:metabolism; D012756:Sheep; D013292:Streptococcus agalactiae / Q000276:immunology*
chemical_list: D006460:Hemolysin Proteins; D010447:Peptide Hydrolases; D012413:Rubidium