Intestinal macrophages involved in the homeostasis of the intestine have the potential for responding to LPS.

Recently, there has been interest in the tertiary functions of food, those that maintain human health. Moreover, lipopolysaccharides (LPS), which are components of Gram-negative bacteria, have been found to be highly effective in activating innate immunity and have been rediscovered as new functional food materials. In this review, we discuss the significance of LPS as a food component with reference to these tertiary functions based on recent findings. There is special emphasis on the plasticity of responses to LPS by intestinal macrophages. According to the macrophage-network theory, local macrophages cooperate with other tissue macrophages. For this reason, this review also discusses the possibility that information is transferred throughout the body from intestinal macrophages.