Food allergies can have significant effects on morbidity and quality of life. Therefore, the development of efficient approaches to reduce the risk of developing food allergies is of considerable interest.
French Researchers published on Applied and Environmental Microbiology journal a study where they have identified and selected probiotic strains with preventive properties in allergy, using a combination of in vitro and in vivo approaches. To that end, thirty one strains belonging to bifidobacteria and lactic acid bacteria were screened for their immunomodulatory properties in two cellular models, namely human peripheral blood mononuclear cells (PBMCs) and T-helper 2 (Th2) skewed murine splenocytes. Six strains inducing a high IL10/IL12p70 ratio and a low secretion of IL-4 on both cellular models were selected, and their protective impact was tested in vivo in a murine model of food allergy to β-lactoglobulin.
Three strains showed a protective impact on sensitization with a decrease in allergen-specific IgE as well as on allergy with a decrease in mast cell degranulation. Analysis of the impact of these three strains on the T-helper balance revealed different mechanisms of action: the L. salivarius LA307 strain proved to block both Th1 and Th2 responses while the B. infantis LA308 strain induced a pro-Th1 profile and the L. rhamnosus LA305 strain induced both pro-Th1 and regulatory responses.
These results demonstrate that combination of both in vitro and in vivo screening is effective in probiotic strain selection and allowed identification of three novel probiotic strains which are active against sensitization in mice.
