Influence of Microbial Flora on Macrophages

The purpose of this article was to collect the existing data on the influence of bacterial flora on the properties of macrophages which represent one of the first lines of non specific defence against microbial invasion and tumours. To the effects of indigenous microflora were added those of lactic acid bacteria potentially usable as dietary supplements which have been widely investigated. The results of these studies indicate that functions important in host defence, such as chemotaxis, phagocytosis, cytotoxicity, intracellular killing of bacteria as well as cytokine production, appear to be, at least in part, under the control of the indigenous microflora. Though lactic acid bacteria exert stimulating effects on macrophage functions, their impact is less clearly established and seems to be strain- and test system-dependent. Results showing macrophage activation in humans by orally administered lactic bacteria are very limited and more studies are needed to correlate the stimulation of macrophage functions and positive health effects of these probiotic products. Keywords: macrophage, immunity, microbial flora, lactic acid bacteria, probiotics.