In vitro and in vivo screening of candidate probiotic strains for their anti-allergic properties

There is considerable interest in generating efficient approaches that may reduce the risk of developing food allergy which is responsible for significant effects on morbidity and quality of life. Alterations in the sequential bacterial colonization of the gut could be responsible for a T-helper balance deviation, a major factor in the rise of allergic diseases. Therefore, a modulation of the gut microbiota is appealing for preventing and managing allergic diseases and this notion supports the use of probiotics.  

Our aim is to select a probiotic strain with preventive properties in allergy using a combination of in vitro and in vivo approaches.

A panel of 33 strains was screened for their immunomodulatory properties on hPBMC and on splenocytes from ovalbumin-sensitized mice. Three Lactobacillus and three Bifidobacterium inducing a low IL12/IL10 ratio on both models were tested in a murine model of food allergy to beta-lactoglobulin (BLG). Three strains showed a protective impact on sensitization with a decrease in allergen specific IgE and on allergy with a decrease in mast cell degranulation. Among them, L. rhamnosus LA305 decreased the secretion of total and allergen specific IgE as well as blood mouse mast cell protease-1. In sensitized mice, the activation of Th17 pathway in ileum, the suppression of Th2 response in mesenteric lymph nodes, and the production of IFN-γ by BLG-stimulated splenocytes suggest a restoration of the T-helper balance that may, in part, explain the protective effect of LA305 on allergy beneficial.

This project is co-funded by the ANRT and PiLeJe Group.