Studies on Rickettsial Toxins

Abstract

Summary Comparison of the action of toxic viable Rickettsia mooseri with that of a Boivin type endotoxin from Escherichia coli in mice revealed striking differences. One LD50 of the endotoxin caused a prompt depression in total leukocyte count followed by leukocytosis, whereas 1 LD50 of the toxic rickettsial suspension failed to cause a significant shift in total leukocyte count toward a comparable response pattern. Reticuloendothelial blockade with colloidal iron saccharate markedly increased the susceptibility of mice to the lethal action of the endotoxin, but failed to alter their susceptibility to the toxic action of the rickettsiae. Moreover, mice rendered tolerant to endotoxin remained as susceptible to the rickettsial toxin as normal control mice. It is concluded that the mouse lethal toxin of R. mooseri and classic bacterial endotoxin differ significantly in several important properties.