title: High in vitro endotoxin responsiveness of macrophages from an endotoxin-resistant wild rodent species, Sigmodon hispidus.
abstract: It has been reported that macrophages primarily mediate endotoxin shock and cell death by synthesizing and releasing cytokines, largely tumor necrosis factor (TNF) and interleukin-1 (IL-1). However, macrophages from some laboratory mouse strains such as C3h/HeN are unresponsive to endotoxin both in vivo and in vitro. We found members of a wild rodent species, Sigmodon hispidus, to also be extremely resistant to bacterial endotoxin challenge. Intravenous administration of up to 100,000 micrograms/kg body mass of Escherichia coli O26:B6 endotoxin did not cause lethality in adult S. hispidus. In contrast to the endotoxin-resistant mouse strain, peritoneal macrophages derived from S. hispidus were responsive to in vitro endotoxin challenge as measured by high levels of TNF and IL-1 activity in supernatants of macrophage cultures. Thus, in vitro macrophage responsiveness to endotoxin does not always indicate high host sensitivity to endotoxin challenge.
authors.affiliation: Department of Zoology, Oklahoma State University, Stillwater 74078.
authors.forename: C B
authors.initials: CB
authors.lastname: Dabbert
authors.forename: R L
authors.initials: RL
authors.lastname: Lochmiller
authors.forename: J R
authors.initials: JR
authors.lastname: Zhang
authors.forename: C W
authors.initials: CW
authors.lastname: Qualls
authors.forename: K
authors.initials: K
authors.lastname: Burnham
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004731:Endotoxins / Q000633:toxicity*; D007375:Interleukin-1 / Q000378:metabolism; D007928:Lethal Dose 50; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D016205:Sigmodontinae / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D004731:Endotoxins; D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha