Pokrovsky, V.K., Timchenko, N.F., Nedashkovskaya, E.P., Grigoryeva, E.A.

iological properties of heat-labile lethal toxin of Yersinia pseudotuberculosis

Research Institute of Epidemiology and Microbiology, Vladivostok; Gamaleya Research Institute of Epide­miology and Microbiology, Moscow, Russia

The aim of the study was to assess the biological properties of heat-labile lethal protein toxin of Y.pseudotuberculosis. Toxin was extracted from Y.pseudotuberculosis strain 2517 type III serovar pYV-. The toxin killed mice 1 — 3 days after intraperitoneal administration (LD₅₀=0.3 mcg of the protein). Heating at 56°C during 30 min inactivated lethal activity of the toxin. It had a dose-dependent dermonecrotic effect during intracutaneous administration in rabbits. Hyperimmune rabbit serum to the toxin was obtained. Incubation of the toxin (LD₁₀₀=1.2 mcg of the protein) with the serum at 37°C during 30 min resulted in neutralization of lethal and dermonecrotic effects. The toxin did not have the cytotoxic effect on HeLa, Hep-2, and SPEV cells, but showed hemolytic activity to human and animal erythrocytes, and weak mitogenic activity to splenic cells of CBA line mice compared with control mitogen (concanavalin A).
Zh. Mikrobiol. (Moscow), 2008, No. 6, P. 63—66