Studies on extracellular proteins from Staphylococcus aureus: VII. Studies on β-haemolysin

Abstract

Some properties of an extensively purified β-haemolysin were investigated 4. The purified β-lysin was confirmed to release N- acylsphingosine from sphingomyelin, thus being a sphingomyelinase C. The haemolytic spectrum for different red blood cells was investigated and sheep erythrocytes were found to be most sensitive. No synergism or antagonism was noticed on the combined action of staphylococcal α-, β-, and δ-haemolysin on sheep, rabbit, or human red blood cells. Purified β-haemolysin was lethal for rabbits, guinea pigs, mice (10–100 μg), and chicken embryos (0.25-10 μg). Both effects were inhibited by an anti-β-serum. Human thrombocytes and their α-granules were also rapidly lysed, while human leucocytes and bacterial protoplasts were resistant for a comparative dose. These observations on the susceptibility of different cells are compatible with the different phospholipid composition of these cell membranes. No β-haemolytic activity was found in the staphylococcal cell fractions. Thus, β-haemolysin is probably a true extracellular protein, actively excreted during growth.