Fermentation products: immunological effects on human and animal models

Abstract Abstract• What Are Fermented Products?• Fermentation Products are Modulators of the Intestinal Microbiota• Fermentation Products Modulate the Immune System• In Vitro Studies• Animal Studies• Discussion• Statement of Financial Support• References• Author information Infant formulas have been shown to influence the development of the gut microbiota. Besides the probiotic- and prebiotic-containing formulas, fermented milk–based infant formulas offer an additional means for modulation of gut immunity and/or gut microbiota. These formulas are produced by the fermentation of cow’s milk with specific lactic acid bacteria strains, followed by heat treatment; they do not contain viable bacteria or added prebiotic oligosaccharides but contain specific products resulting from the fermentation process. This review is focused on the effects of fermentation products, distinguishing them from those of living bacteria and prebiotic compounds on the immune system. Besides the possible modulation of gut microbiota composition, in vitro and in vivo studies suggest that specific fermentation products can actively participate in the establishment of immune balance and oral tolerance. Although further research is needed to confirm the clinical benefits observed in infants to better characterize the active fermentation compounds and to delineate the involved pathways, these fermented formulas appear to deserve interest. At a glance Figures View all figures Figure 1: Phenotype and activation of dendritic cells. (a) Dendritic cell (DC) phenotype. Staining of markers CD80, CD83, CD86, and CD25 was analyzed by cytometry for immature DCs (iDCs) and DCs treated with 50 ng/ml of LPS (LPS-DCs) or with 50 µg/ml of BbC50sn (BbC50sn-DCs). Secretion of (b) IL-12, (c) IL-10, (d) IFN-γ, and (e) IL-6 by iDCs, LPS-DCs, and BbC50sn-DCs, assessed by ELISA. Each point represents a donor, and bars represent means. For statistical data, the Wilcoxon test was used; *P < 0.05. BbC50sn and LPS induced maturation, and IL-10 secretion was higher for BbC50sn-DCs. ELISA, enzyme-linked immunosorbent assay; IFN, interferon; IL, interleukin; LPS, lipopolysaccharide. Full size image View in article Figure 2: Dendritic cell (DC) phenotype analysis by cytometry. CD83, CD86, and HLA-DR were studied on DCs in the presence of (a) casein-hydrolysate in the presence of BbC50, (b) whey hydrolysate fermented by BbC50, or (c) whey hydrolysate without BbC50. The x-axes represent the intensity of fluorescence (IF) and the y-axes the cell counts. Bold histograms represent specific staining of the indicated cell-surface markers, and thin histograms correspond to isotype controls: DC maturation (upregulation of CD83, CD86, and HLA-DR) is observed only when the fermentation process occurs with whey hydrolysate medium. HLA, human histocompatibility leukocyte antigen. Full size image View in article