Platelet-activating factor is a mediator in tumor necrosis factor/galactosamine-induced lethality.

We here report that administration to mice of WEB2170, a potent platelet-activating factor (PAF) receptor antagonist, prevents both PAF-induced and murine tumor necrosis factor (TNF)-induced lethality in galactosamine (GalN)-sensitized mice. Furthermore, we demonstrate that pretreatment with alpha 1-acid glycoprotein (AGP) or interleukin-1 (IL-1) protects against TNF-induced, but not against PAF-induced lethality. We conclude that PAF is a mediator in TNF/GalN-induced lethal shock, but that the protection conferred by AGP or IL-1 pretreatment is not at the level of scavenging PAF.