The two Staphylococcal bi-component toxins, leukocidin and gamma-hemolysin, share one component in common

Abstract

Staphylococcal bi-component toxins, leukocidin and γ-hemolysin, consist of two protein components, i.e. F and S for leukocidin and HγI and HγII for γ-hemolysin. In this study we purified HγI and HγII to homogeneity from the culture medium of Staphylococcus aureus RIMD 310925 and compared their properties with those of F and S purified from the same source. The N-terminal 59- and C-terminal 2-residue amino acid sequences, apparent molecular mass, and isoelectri point of purified HγI were the same as those of F. In an Ouchterlony double diffusion test a fused line without spur was formed between F and HγI using either anti-F or anti-HγI antibodies. A synergistic action of F and HγII caused hemolysis of human red blood cells, and HγI acted synergistically with S to exhibit leukocidin activity. We conclude that the two toxins share one protein component (F = HγI) in common and leukocidin- and γ-hemolysin-specific activities are determined by S and HγII, respectively. It is also reported that the N-terminal 58-residue sequence of HγII is 72% similar to the corresponding sequence of S.