A new model for the study of experimental amyloid is described using parenteral administration of endotoxin. The differential responses in the various strains of mice examined suggested that genetic factors may be involved in murine MYLOID is a fibrillar glycoprotein found A in the tissues of man and animals under a variety of clinical and laboratory conditions.l Numerous procedures have been used for the induction of experimental amyloid. These include the administration of live or killed bacteriaz4 and the repeated injection of various macromolecular substances such as serum proteins,6s6 ribonucleic acid,7Vs adjuvant?JO and ~asein.~Jl Recently, we reported that injection of E. coli endotoxin induced amyloid in mice.12 The histologic findings and strain differences noted simulated the amyloid produced in mice by repeated injections of casein.13
In this study, evidence is presented which suggests that endotoxins may be responsible for the amyloidosis induced by repeated parenteral administration of casein. Our findings in six different strains of mice using E. coli endotoxin for induction of amyloid amyloid formation. Many similarities were noted between casein-and endotoxin-induced amyloidosis. It is suggested that endotoxin may be involved in the pathogenesis of several forms of experimental amyloidosis.
are reported. The immunoglobulin responses and reticuloendothelial activity after repeated administration of endotoxin were also examined. Commercially obtained and a highly purified preparation of Salmonella endotoxin were studied for their ability to induce amyloid. The possible role of endotoxin in some of the models of experimental amyloid induction is discussed.
MATERIALS AND METHODS
Animals
Mice were obtained from the Rodent and Rabbit Production Section, Animal Production Unit (NIH). The strains included CSH/Hen, AKR, AL/N, C57BL/6JN, Balb/c AnN, and White Swiss (G.P.). Male mice, 6 to 7 weeks old, were used in each of the experiments. New Zealand albino rabbits of either sex, weighing approximately 2 Kg., were used for bioassay of endotoxin preparations.