Radioprotective Properties of Detoxified Lipid A from Salmonella minnesota R595
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
Pagination or Media Count:
In the past, the toxicity of bacterial lipopolysaccharide LPS or its principal bioactive component, lipid A, has detracted from their potential use as radioprotectants. Recently, a relatively nontoxic monophosphoryl Lipid A LAM that retains many of the immunobiologic properties of LPS has been isolated from a polysaccharide deficient Re mutant strain of Salmonella minnesota R595. The ability of the native endotoxic goycolipid GL from S. minnesota R595 as well as diphosphoryl lipid A LAD and nontoxic monophosphoryl lipid A LAM derived from GL to protect LPS responsive CD2F1 or C3HHeN and nonresponsive C3HHeJ mice from cobalt 60 gamma irradiation has been studied. Administration of GL, LAD, or LAM to CD2F1 or C3HHeN mice 400 microgramskg 24 h prior to exposure provided significant radioprotection. No protection was afforded to C3HHeJ mice. Experiments were also conducted to determine the relative abilities of GL, LAD, and LAM to stimulate hematopoiesis as reflected by the endogenous spleen colony E-CFU assay. Protection was not correlated with the ability of these substances to increase E-CFUs or to induce colony-stimulating activity CSA.