[Molecular nature of the pathogenic effect induced by B. cereus]

The paper shows that biological properties of the DL-toxin are determined by structural particularities of this substance. It is supposed that the component B with mol. mass of 42,000 performs the ligand function enabling fixation of the toxin on a target cell. The component A with mol. mass of 37,000 has been characterized as an activator in reproducing oedematous and diarrheagenic effect. The component C activates the induction of the lethal effect. The optimal ratios of these components needed for reproduction of the respective biological effects are: B + A-6:1; B + C-5:1. In terms of specific activity, cereolysine is more active than the DL-toxin in inducing of the lethal effect. However, the later has bigger capability to break vascular permeability and it also reveals enteropathogenic properties. It is shown that among the exoproteins, produced by the strain 96 of B. cereus, the contents of the DL-toxin considerably exceeds the one of cereolysine. Thus, the DL-toxin plays the dominating role in reproducing oedematous, diarrheagenic and lethal effects.