title: Comparative efficacy and toxicity of a ribosomal vaccine, acetone-killed cells, lipopolysaccharide, and a live cell vaccine prepared from Salmonella typhhimurium.
abstract: The protective and toxic properties of a ribosomal vaccine prepared from Salmonella typhimurium W118-2 were systematicaly compared with those of an acetone-killed whole cell vaccine, purified lipopolysaccharide, and living cells in CD-1 mice. Tests of graded immunizing doses of each vaccine against several  challenge doses of live strain W118-2 showed that, although the protection given by ribosomes approached the levels of protection conferred by living organisms, acetone-killed cells administered in appropriate dosages provided levels of protection comparable to that of ribosomes. Lipopolysaccharide was found to be significantly less protective than the other vaccines. On a dry-weight basis, ribosomes were the least toxic with a 50% toxic dose (TD50) of 5,000 microgram; acetone-killed cells had an intermediate TD50 of 1,400 microgram; and lipolysaccharide was the most toxic, with a TD50 of 320 microgram. The dose of each vaccine that protected 50% of the mice against a challenge of 1,00 times the 50% lethal dose was determined and divided by the TD50 to give the therapeutic index. This ratio also indicated that the ribosomes and acetone-killed cells were equally effective, whereas lipopolysaccharide was markedly inferior.
mesh_terms: D000096:Acetone / Q000494:pharmacology; D000818:Animals; D001428:Bacterial Vaccines / Q000633:toxicity; D005260:Female; D008070:Lipopolysaccharides / Q000633:toxicity; D051379:Mice; D011135:Polysaccharides, Bacterial / Q000633:toxicity; D012270:Ribosomes / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000517:prevention & control*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000633:toxicity
chemical_list: D001428:Bacterial Vaccines; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial; D014613:Vaccines, Attenuated; D000096:Acetone