Epidemiological studies identified raw cow’s milk consumption as an important environmental exposure that prevents allergic diseases. In the present study, we investigated whether raw cow’s milk has the capacity to induce tolerance to an unrelated, non-milk, food allergen. Histone acetylation of T cell genes was investigated to assess potential epigenetic regulation. Female C3H/HeOuJ mice were sensitized and challenged to ovalbumin. Prior to sensitization, the mice were treated with raw milk, processed milk, or phosphate-buffered saline for eight days. Allergic symptoms were assessed after challenge and histone modifications in T cell-related genes of splenocyte-derived CD4⁺ T cells and the mesenteric lymph nodes were analyzed after milk exposure and after challenge. Unlike processed milk, raw milk decreased allergic symptoms. After raw milk exposure, histone acetylation of Th1-, Th2-, and regulatory T cell-related genes of splenocyte-derived CD4⁺ T cells was higher than after processed milk exposure. After allergy induction, this general immune stimulation was resolved and histone acetylation of Th2 genes was lower when compared to processed milk. Raw milk reduces allergic symptoms to an unrelated, non-milk, food allergen in a murine model for food allergy. The activation of T cell-related genes could be responsible for the observed tolerance induction, which suggested that epigenetic modifications contribute to the allergy-protective effect of raw milk.

Non-communicable diseases are increasing and have an underlying low-grade inflammation in common, which may affect gut health. To maintain intestinal homeostasis, unwanted epithelial activation needs to be avoided. This study compared the efficacy of butyrate, propionate and acetate to suppress IFN-γ+/−TNF-α induced intestinal epithelial activation in association with their HDAC inhibitory capacity, while studying the canonical and non-canonical STAT1 pathway. HT-29 were activated with IFN-γ+/−TNF-α and treated with short chain fatty acids (SCFAs) or histone deacetylase (HDAC) inhibitors. CXCL10 release and protein and mRNA expression of proteins involved in the STAT1 pathway were determined. All SCFAs dose-dependently inhibited CXCL10 release of the cells after activation with IFN-γ or IFN-γ+TNF-α. Butyrate was the most effective, completely preventing CXCL10 induction. Butyrate did not affect phosphorylated STAT1, nor phosphorylated NFκB p65, but inhibited IRF9 and phosphorylated JAK2 protein expression in activated cells. Additionally, butyrate inhibited CXCL10, SOCS1, JAK2 and IRF9 mRNA in activated cells. The effect of butyrate was mimicked by class I HDAC inhibitors and a general HDAC inhibitor Trichostatin A. Butyrate is the most potent inhibitor of CXCL10 release compared to other SCFAs and acts via HDAC inhibition. This causes downregulation of CXCL10, JAK2 and IRF9 genes, resulting in a decreased IRF9 protein expression which inhibits the non-canonical pathway and CXCL10 transcription.

Raw cow’s milk was previously shown to suppress allergic symptoms in a murine model for food allergy. In the present study, we investigated the contribution of fat content and heat-sensitive milk components to this allergy-protective effect. In addition, we determined the potency of alkaline phosphatase (ALP), a heat-sensitive raw milk component, to affect the allergic response. C3H/HeOuJ mice were treated with raw milk, pasteurized milk, skimmed raw milk, pasteurized milk spiked with ALP, or phosphate-buffered saline for eight days prior to sensitization and challenge with ovalbumin (OVA). Effects of these milk types on the allergic response were subsequently assessed. Similar to raw milk, skimmed raw milk suppressed food allergic symptoms, demonstrated by a reduced acute allergic skin response and low levels of OVA-specific IgE and Th2-related cytokines. This protective effect was accompanied by an induction of CD103⁺CD11b⁺ dendritic cells and TGF-β-producing regulatory T cells in the mesenteric lymph nodes. Pasteurized milk was not protective but adding ALP restored the allergy-protective effect. Not the fat content, but the heat-sensitive components are responsible for the allergy-protective effects of raw cow’s milk. Adding ALP to heat-treated milk might be an interesting alternative to raw cow’s milk consumption, as spiking pasteurized milk with ALP restored the protective effects.

The composition and activity of the intestinal microbial community structures can be beneficially modulated by nutritional components such as non-digestible oligosaccharides and omega-3 poly-unsaturated fatty acids (n-3 PUFAs). These components affect immune function, brain development and behaviour. We investigated the additive effect of a dietary combination of scGOS:lcFOS and n-3 PUFAs on caecal content microbial community structures and development of the immune system, brain and behaviour from day of birth to early adulthood in healthy mice. Male BALB/cByJ mice received a control or enriched diet with a combination of scGOS:lcFOS (9:1) and 6% tuna oil (n-3 PUFAs) or individually scGOS:lcFOS (9:1) or 6% tuna oil (n-3 PUFAs). Behaviour, caecal content microbiota composition, short-chain fatty acid levels, brain monoamine levels, enterochromaffin cells and immune parameters in the mesenteric lymph nodes (MLN) and spleen were assessed. Caecal content microbial community structures displayed differences between the control and dietary groups, and between the dietary groups. Compared to control diet, the scGOS:lcFOS and combination diets increased caecal saccharolytic fermentation activity. The diets enhanced the number of enterochromaffin cells. The combination diet had no effects on the immune cells. Although the dietary effect on behaviour was limited, serotonin and serotonin metabolite levels in the amygdala were increased in the combination diet group. The combination and individual interventions affected caecal content microbial profiles, but had limited effects on behaviour and the immune system. No apparent additive effect was observed when scGOS:lcFOS and n-3 PUFAs were combined. The results suggest that scGOS:lcFOS and n-3 PUFAs together create a balance—the best of both in a healthy host.

It is vital that Immune fitness, i.e., how well the immune system functions and reacts to challenges, can be reliably be examined. The current study aimed to compare immune fitness with assessments of saliva biomarkers of systemic inflammation. N = 108 healthy young adults (18–30-year-old students of Utrecht University, the Netherlands) participated in the study. A saliva sample was collected for biomarker assessment (Interleukin (IL)-1β, IL-6, IL-8, IL-10, immunoglobulin A (IgA), and tumor necrosis factor-alpha (TNF-α), and c-reactive protein (CRP). Additionally, a survey was completed to assess immune fitness, mood, mental resilience, and quality of life. The correlations between the biomarker assessments, immune fitness and mood were determined. No significant correlations between immune fitness and biomarkers of systemic inflammation were found. Significant sex differences in correlations with immune fitness were demonstrated for loneliness (significant only in men) and fatigue (significant only in women). For both sexes, immune fitness correlated significantly with anxiety, mental resilience, and quality of life. No significant correlations were found between immune fitness and saliva biomarkers of systemic inflammation. Immune fitness correlated significantly with anxiety, mental resilience, and quality of life. Sex differences were demonstrated in the relation of immune fitness with loneliness and fatigue. Future research should further investigate factors that may influence the relationship between immune fitness, mood, and biomarkers of systemic inflammation, including underlying psychological mechanisms of possible sex differences.

Background/Objectives: The gut microbiome has an important role in immune regulation, and dietary interventions that support a balanced microbiota may help to prevent the development of allergic asthma. Dietary fibers can beneficially affect the intestinal microbiome, but due to the diversity of fiber types, the effects differ. In this study, we investigate the preventive effects of two mixes of short-chain and long-chain (1:1 and 9:1 ratio) fructo-oligosaccharides (FOS) in a mouse model of house dust mite (HDM)-induced allergic asthma. Methods: BALB/c mice received FOS-supplemented (1% w/w) diets before and during intranasal exposures to HDM. Endpoint airway hyperreactivity measurements were performed, followed by the collection of bronchoalveolar lavage fluid (BALF), lung, serum and cecum content. Fecal microbiome composition was determined by DNA sequencing and short-chain fatty acid (SCFA) levels were determined in the cecum, serum and lung. Results: Fecal microbiome analyses revealed an increased abundance of Prevotellaceae after FOS1:1 supplementation in HDM-allergic mice. Additionally, FOS1:1 protected against an HDM-induced increase in basal airway resistance. Both FOS1:1 and FOS9:1 restored the systemic acetate levels in HDM-allergic mice. The two FOS supplementations did not affect HDM-induced inflammatory cell influx in the BALF. However, FOS1:1 increased the frequency of Th1-cells and prevented an HDM-induced increase in the Th2/Th1 balance. Upon ex vivo restimulation with HDM, lung cell suspensions of FOS1:1-fed mice produced less type 2-related cytokines compared to control-supplemented mice, and FOS9:1 followed a similar pattern. Conclusions: Specific short-chain and long-chain FOS ratios differentially affect the microbiome and immune system in a mouse model with HDM-induced allergic airway inflammation. Dietary supplementation with FOS1:1 shifts the immune response away from type 2, suggesting that dietary fibers like FOS1:1 may contribute as a part of a broader strategy to modulate HDM-induced allergic asthma.