Preparation of Biologically Active Plague Murine Toxins labelled with ⁷⁵Se-Methionine

Abstract

ALTHOUGH the physiology and mechanism of action of the plague toxins have been investigated quite extensively, the target organ(s) is still unknown¹. Pasteurella pestis toxin does not remain in a free soluble form either after injection or after infection with a virulent strain. It cannot be detected in the plasma of moribund animals, although whole blood is toxic to mice 48 h after infection. Thus, the toxin may be bound to erythrocytes or other particulate matter (cell debris), which is phagocytosed by macrophages and removed from circulation. This could provide an efficient way of concentrating the toxin in specific organs such as the spleen or the liver, after breakdown of erythrocytes². If the spleen and liver are not the primary targets, the toxin could reach other organs through the circulation and exert its effect.