Comparison of the effect of autoclaved and non-autoclaved live soil exposure on the mouse immune system : Effect of soil exposure on immune system.

BACKGROUND: . Lack of exposure to the natural microbial diversity of the environment has been linked to dysregulation of the immune system and numerous noncommunicable diseases, such as allergies and autoimmune disorders. Our previous studies suggest that contact with soil material, rich in naturally occurring microbes, could have a beneficial immunoregulatory impact on the immune system in mice and humans. However, differences in the immunomodulatory properties of autoclaved, sterile soil material and non-autoclaved, live soil material have not been compared earlier. RESULTS: . In this study, we exposed C57BL/6 mice to autoclaved and live soil powders that had the same rich microbiota before autoclaving. We studied the effect of the soil powders on the mouse immune system by analyzing different immune cell populations, gene expression in the gut, mesenteric lymph nodes and lung, and serum cytokines. Both autoclaved and live soil exposure were associated with changes in the immune system. The exposure to autoclaved soil resulted in higher levels of Rorγt, Inos and Foxp3 expression in the colon. The exposure to live soil was associated with elevated IFN-γ concentration in the serum. In the mesenteric lymph node, exposure to live soil reduced Gata3 and Foxp3 expression, increased the percentage of CD8 + T cells and the expression of activation marker CD80 in XCR1+SIRPα- migratory conventional dendritic cell 1 subset. CONCLUSIONS: . Our results indicate that exposure to the live and autoclaved soil powders is not toxic for mice. Exposure to live soil powder slightly skews the immune system towards type 1 direction which might be beneficial for inhibiting type 2-related inflammation. Further studies are warranted to quantify the impact of this exposure in experimental type 2 inflammation.

The epithelial barrier-protecting properties of a soy hydrolysate.

Enhancing the epithelial barrier function could be a possible strategy to prevent food allergy or reduce its symptoms. Soy hydrolysates containing bioactive peptides could be instrumental in this. In this study, the protective effects of pretreatment with 6 soy hydrolysates on calcium ionophore A23187-induced TEER reduction were studied in T84 cells. The effects of the most potent soy hydrolysate on tight junction gene expression were studied. In order to identify the underlying pathways involved, the barrier disruptor specificity of the effect was studied by comparing the protective effects on TEER and Lucifer Yellow flux after the exposure to barrier disruptors that work via different intracellular pathways, i.e. the disruptors A23187, mellitin, and deoxynivalenol (DON). Preincubation with one of the six hydrolysates protected the epithelial cells from a decrease in TEER induced by A23187 (restored to 105% of the starting point, while A23187 alone decreased to 53% of the starting value) and mellitin (restored to 11% of the starting point, while mellitin alone decreased to 3.8% of the starting value). This soy hydrolysate was found to increase claudin-1 and decrease claudin-2 expression. The protective effect of the hydrolysate on TEER was specific for the barrier disruptors A23187 and mellitin, but was not observed for DON. This observation suggests that the soy hydrolysate may act via PKC isoforms, which are known to lead to changes in the expression of claudin-1 and 2. Our data suggest that specific soy hydrolysates may be designed to strengthen the epithelial barrier which might be instrumental in the management of the barrier function in individuals at risk of developing food allergy.