The two strains were found to inhibit the growth of some pathogens and also to decrease the production of pro-inflammatory compounds by peripheral blood mononuclear cells (PBMCs – key cells in the immune system), according to findings published in Allergy, Asthma & Immunology Research.
“L. salivarius LS01 and B. breve BR03 showed promising probiotic properties and beneficial immunomodulatory activity that are increased when the two strains are used in combination in the same formulation,” wrote researchers from the University of Milan and the IRCCS Galeazzi Orthopaedic Institute (Milan).
Probiotics and the immune response
Probiotics are defined as “live microorganisms that when administered in adequate amounts confer a health benefit on the host”.
In background information in their paper, the Milan-based scientists report that the prevalence of allergic disease in industrialized nations have significantly increased in recent years, with
An immune regulation theory involves a balance between the activity of T-helper 1 (Th1) and T-helper 2 (Th2) cells, and allergies are associated with a disruption of this balance (towards the Th2). Th2 lymphocytes then over-produce IL-4, Il-5, or IL-13, which are involved in the development of the allergic response, they said.
“Several studies showed a reduced incidence of allergy in children treated with specific probiotic strains that were able to decrease the production of Th2 cytokines, keeping the production of Th1 stable,” they wrote. “This evidence strengthens the hypothesis that probiotic strains could be used in the treatment of allergic diseases.”
To deepen our understanding of probiotics and allergies further, the researchers first tested how compatible the two bacterial strains (Bifiderm, Bayer) were by culturing them in a broth together. Results from this showed that there was no inhibition of either strain and both grew the same alone or together.
Antimicrobial tests of the probiotic strains indicated that all pathogens were somewhat inhibited by L. salivarius LS01 alone or in combination with B. breve BR03, but B. breve BR03 alone had no effect on the pathogens.
Finally, the researchers then obtained blood samples from people with allergic asthma and measured cytokine production in the PBMCs in the presence or absence of L. salivarius LS01 and B. breve BR03.
The data indicated that the combination of the strains decreased the secretion of pro-inflammatory cytokines by the PBMCs. This was also associated with an “intense increase” in the production of interleukin-10 (IL-10).
“This cytokine is a powerful inhibitor of proinflammatory cytokines, such as IL-4 and IL-5, and there is evidence that IL-10 mRNA and protein expression are reduced in alveolar macrophages from asthmatic subjects compared to those from non-asthmatic subjects,” they explained. “Furthermore, our analysis highlighted the synergic effect of LS01 and BR03 in stimulating the production of IL-10; indeed, the amount of IL-10 is higher when PBMCs were stimulated with LS01 and BR03 at the same time.
“Interestingly, the probiotic strains tested in this study were able to inhibit the secretion of proinflammatory cytokines, such as TGF-beta, IL-13, and IL-17.
“Further studies should be carried out to assess the clinical impact of LS01 and BR03 in subjects affected by allergic asthma and to develop a cost-effective biotherapy able to improve the symptoms of allergic diseases,” they concluded.
Source: Allergy, Asthma & Immunology Research
July 2015, Volume 7, Number 4, Pages 409-413, doi: 10.4168/aair.2015.7.4.409
“Immunomodulatory Effects of Lactobacillus salivarius LS01 and Bifidobacterium breve BR03, Alone and in Combination, on Peripheral Blood Mononuclear Cells of Allergic Asthmatics”
Authors: L. Drago, E. De Vecchi, A. Gabrieli, R. De Grandi, M. Toscano