LYSINE DEFICIENCY AND HOST RESISTANCE TO ANTHRAX

Abstract

The decrease in resistance to a lethal dose of Bacillus anthracis spores was studied in the Sprague-Dawley rat. Lysine deficiency was induced by placing weanling animals on a diet complete in all known requirements except that the protein source was gluten at a level of 20%. The control diet had casein as the protein source. The animals were maintained on this regimen for 30 days. Using a challenge dose of 107 spores the mortality is increased from 29% in controls to 82% in the deficient animals. Several parameters have been measured, the most significant being a decrease in the number of circulating leukocytes and platelets in the deficient animals. Evidence for a prerenal cystemia is present, but its role in the decreased resistance is still unclear. Reticuloendothelial system (RES) activity in the deficient animals is signficantly decreased. Using I131 labelled spores, it was shown that the fate of the spores in the two groups of animals is different. It is postulated that the decreased ability of the RES to clear and destroy the organisms is a major factor in the decreased resistance.