About this Research Topic
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, influencing, among others, the immune system. After ingestion, their effects are mediated through modulation of the resident microbiota composition, bioactive molecules production (e.g. short-chain fatty acids, SCFA), and changes in epithelial and immune intestinal cells. In recent years, elegant animal models and complex in vitro approaches (cell-bacteria co-cultures and organoids) have been designed to elucidate the underlying molecular mechanisms involved. Overall, much evidence exists in humans and animal models about probiotic effects in preventing infections, reinforcing vaccination, modulating allergy, counteracting inflammation, etc. These effects are strain associated.
Prebiotic components are known to promote the selective growth of certain beneficial bacteria, and can be used in combination with probiotic strains (synbiotics). Besides the direct effect of these compounds on bacterial composition and functionality, they can also impact on the immune system and host defence mechanisms through direct interaction with pathogens or with intestinal or immune cells. The prebiotic concept is relatively new, compared to probiotics, as such there are fewer publications in this growing area to date.
In recent years a new “biotic” type has been proposed, postbiotics. This concept, although not officially defined, refers to the components derived from microbial fermentation, in a particular matrix, that promote health. Thus, postbiotics can include many components including microbial cell-wall fractions but, also particular constituents such as extracellular or surface-associated proteinaceous molecules and exopolysaccharides (EPS), or microbial metabolites derived from carbohydrate fermentation (SCFAs) or protein degradation (branched-chain fatty acids, BCFAs). The study of the impact of postbiotics administration on human health is still a pending task.
The goal of this Research Topic is to present the current state-of-the-art research on the effects of the microbial modulators, also termed “biotics”, (probiotics, prebiotics, synbiotics and postbiotic) on immune function. We welcome the submission of Original Research Articles and Clinical Trials, as well as Reviews, Systematic Reviews, Mini-Reviews, Hypothesis and Theory, Perspectives, that allow connecting the molecular mechanisms with the effects of such microbial modulators.
We welcome articles focused on, but not limited to, the following sub-topics:
1. Effects of pro-, pre-, syn and post-biotics and the immune system.
2. Studies describing the molecular mechanisms of any of these microbial modulators in relation to the immune system and microbiota.
3. Comparison of effectiveness between these compounds.
4. Current animal and in vitro approaches and models to study the impact of these compounds on the immune response.
5. Associations between microbial modulator administration and prevention of immune-mediated diseases, including allergies, inflammation, autoimmunity, but also infection and vaccination.
6. Role of the “biotic” components in the of the immune system and microbiome development in early life, as well in the prevention/treatment of immunosenescence.
7. Role of the microbial modulators in breast milk and studies of their addition in infant formulas.
Keywords: probiotics, prebiotics, synbiotics, postbiotics, SCFA, microbiota, oligosaccharides, metabolites, immune response, health outcomes
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.