Role of Protein Component of Endotoxin in Modification of Host Reactivity. ∗

Summary

The influence of endotoxins of varying nitrogen content on water intake and numbers of hemolysin-forming spleen cells in mice and on delayed skin reactivity in rabbits has been investigated. Pretreatment with an aqueous-ether endotoxin of S. enteritidis results in heightened reactivity to a subsequent test dose of the aqueous-ether or protein-free (Ribi) endotoxin, whereas pretreatment with the protein-free endotoxin fails to modify subsequent reactivity to either endotoxin. Similarly, pretreatment with the Boivin endotoxin of S. abortus equi increases reactivity on subsequent test with the Boivin or Westphal endotoxin, whereas pretreatment with the partially deproteinized Westphal endotoxin does not enhance reactivity to subsequent test with either endotoxin. The implications of these findings for the hypothesis that adult host reactivity to endotoxins is contributed to by an acquired delayed hypersensitivity are discussed.