Lipopolysaccharide desensitization of macrophages provides protection against Yersinia enterocolitica-induced apoptosis.

Pathogenic Yersinia spp. uncouple an array of signal transduction pathways in macrophages to disrupt their response to infection. This compels the macrophage to undergo apoptosis. Our study shows that macrophages that had acquired tolerance to Yersinia infection by preexposure to lipopolysaccharide were considerably protected against Y. enterocolitica-induced apoptosis. The desensitization of macrophages by lipopolysaccharide, which is thought to be a self-protective, adaptive response to sustained bacterial stimulation, may represent an immune mechanism that aids in overcoming Yersinia-mediated apoptosis and infection.