title: Sensitizing anthrax lethal toxin-resistant macrophages to lethal toxin-induced killing by tumor necrosis factor-alpha.
abstract: Macrophages from different inbred mouse strains exhibit striking differences in their sensitivity to anthrax lethal toxin (LeTx)-induced cytolysis. Although LeTx-induced cytolysis of macrophages plays an important role in the outcome of anthrax infection, the sensitivity of macrophages in vitro does not correlate with in vivo susceptibility to infection of Bacillus anthracis. This divergence suggests that additional factors other than LeTx are involved in the cytolysis of LeTx-resistant macrophages in vivo. We found that LeTx-resistant macrophages became sensitive to LeTx-induced cytolysis when these cells were activated by bacterial components. Tumor necrosis factor-alpha induced by bacterial components was a key factor that cooperated with LeTx in inducing LeTx-resistant macrophage death. Tumor necrosis factor-alpha/LeTx-induced death of LeTx-resistant macrophages was dependent on mTor (mammalian target of rapamycin), but independent of caspases. Our data indicate that host responses to anthrax infection contribute to cytolysis of LeTx- resistant macrophages.
authors.affiliation: Department of Immunology, Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Sung O
authors.initials: SO
authors.lastname: Kim
authors.forename: Qing
authors.initials: Q
authors.lastname: Jing
authors.forename: Kasper
authors.initials: K
authors.lastname: Hoebe
authors.forename: Bruce
authors.initials: B
authors.lastname: Beutler
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Duesbery
authors.forename: Jiahuai
authors.initials: J
authors.lastname: Han
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000494:pharmacology; D000942:Antigens, Bacterial; D001427:Bacterial Toxins / Q000494:pharmacology*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D002470:Cell Survival; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D010641:Phenotype; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases; D013997:Time Factors
chemical_list: D017304:Annexin A5; D000942:Antigens, Bacterial; D001427:Bacterial Toxins; C030325:anthrax toxin; D004247:DNA; D011494:Protein Kinases; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases; D020169:Caspases