Immunomodulatory and antiinflammatory mechanisms of probiotics

Probiotic bacteria are able to provide and maintain the host intestinal homeostasis by stimulating immune responses directly or via modulation of the autochnous microbiota. In this context, this chapter describes the main mechanisms of action performed by probiotic strains focused in Lactobacillus and Bifidobacterium species, as they have being well characterized and are known to produce a plethora of compounds presenting antiinflammatory activity. In the intestinal microbiota, short chain fatty acids and vitamins produced from probiotics can alter intestinal permeability and strengthen intercellular junctions, making macromolecules more selective, in addition to the attachment of surface layer proteins are important to initiate a cross-response between bacterial components and host defenses such as epithelial barrier functions and antiinflammatory responses. Understanding the immunomodulatory effects of probiotics has gained increasing attention because their potential to prevent or alleviate certain pathologies for which appropriate medical treatment is not yet available. This chapter may help to understand the molecular mechanisms of probiotic bacteria associated with antiinflammatory functions in host cells.