Isolation and some properties of beta-hemolysin produced by Nocardia asteroides.

An intracellular beta-hemolysin capable of lysing human, sheep and cow erythrocytes but not cells from some other animals was isolated from the cell walls of the three developmental cell-forms of Nocardia asteroides and characterised. The spherical cell-forms contained the highest amounts of the hemolysin (100 h.u./mg protein) and the least LD50 for mice suggesting that this may be the cell-form most pathogenic to susceptible animals. The hemolysin has the properties of a protein, was pH stable and sensitive to both catabolite repression and temperature. The activity of the hemolysin was enhanced by Ca++ and Na+ ions. The hemolysin was immunogenic in rabbits.