Evidence for a Common Hapten Associated with Endotoxin Fractions of E. coli and other Enterobacteriaceae. ∗

Summary

Sera from rabbits immunized at 3 different laboratories with E. coli 014 antigens prepared from boiled whole cultures or with Boivin type extracts agglutinate human and sheep erythrocytes coated with lipopoly-saccharides or crude 0 antigen type preparations from a wide variety of E. coli and other Enterobacteriaceae but do not produce heterologous bacterial agglutination or precipitin formation. Inhibition and absorption studies suggest that the observed phenomena are due to a hapten associated, but not necessarily identical, with the crude endotoxin moiety of Enterobacteriaceae which is so structured in E. coli 014 as to be able to induce antibody formation.