STUDIES WITH BRUCELLA ENDOTOXIN IN HUMANS: THE SIGNIFICANCE OF SUSCEPTIBILITY TO ENDOTOXIN IN THE PATHOGENESIS OF BRUCELLOSIS

Abstract

Sera from patients with brucellosis were found to contain precipitins for brucella endotoxin and to confer passive protection against the lethality of brucella endotoxin for mice. The injection of sufficient quantities of brucella endotoxin into humans caused fever, chills, sweating, myalgia, headache, and malaise. Individuals who had been infected by brucellae were much more susceptible to these effects than noninfected control subjects. The degree of reaction to brucella endotoxin was more severe in those individuals who had experienced active brucellosis (either present or in the past) and in those with more intense intradermal reactions to brucella skin test antigens. Resistance to the toxicity of brucella endotoxin developed after repeated injections of endotoxin. Hydrocortisone or adrenocorticotropic hormone suppressed or ameliorated reactions to brucella endotoxin in 5 patients. Injections of brucella endotoxin into humans caused the formation of serum precipitins for the endotoxin and serum agglutinins for brucella cells. It is suggested that brucella endotoxin contributes significantly to the pathogenesis of illness in brucellosis, particularly in the infected host who has been made more susceptible to its toxicity.