Characterization of Candidate Anti-Allergic Probiotic Strains in a Model of Th2-Skewed Human Peripheral Blood Mononuclear Cells

Abstract

Background: Pre-clinical and clinical studies have evaluated the efficacy of probiotics in allergy. However, predictive in vitro systems for rational strain selection are still missing. Methods: We developed a novel in vitro screening system for the characterization of probiotics with anti-allergic potential. In this model, human peripheral blood mononuclear cells (PBMC) from healthy donors (n = 68) were skewed towards a Th2 cytokine phenotype by culture with IL-4 and anti-CD40, to resemble cells from allergic donors. Th2-skewed cells were then co-cultured with probiotics; a total of 35 strains were tested. Levels of IFN-γ, IL-10, IL-5 and 7 additional cytokines in culture supernatants were determined by ELISA or multiplex assay. Gene expression was assessed by real-time PCR. For validation, splenocytes from ovalbumin-primed mice and PBMC from grass-allergic donors were restimulated with respective antigen and co-cultured with probiotics, and cytokine profiles were correlated. Results: Culture with IL-4 and anti-CD40 antibody induced secretion of IL-5 from PBMC, indicative of induction of a Th2 phenotype. Cytokine profiles induced by probiotics were strain specific even though species- and genus-specific clustering was observed for many strains by principal component analysis. This was paralleled by mRNA levels of the corresponding genes such as increased Tbet and reduced GATA-3 gene expression. Cytokine profiles induced by probiotics in PBMC stimulated with IL-4 and anti-CD40 correlated with those obtained from allergen-stimulated murine splenocytes or human PBMC from grass-allergic donors. Conclusions: Cytokine profiling of probiotic strains with IL-4-/anti-CD40-stimulated PBMC allowed to determine the effect of probiotics on Th2-skewed cells and thus to classify probiotic strains with anti-allergic potential.

Three Novel Candidate Probiotic Strains with Prophylactic Properties in a Murine Model of Cow's Milk Allergy

“…In contrast, the LA307 strain showed a discrete cytokine profile in MLNs and splenocytes, with a low production of Th1, Th2, and Treg cytokines. Holvoet et al suggested that such low-key cytokine patterns induced by probiotics may be associated with a homeostatic effect and may be an alternative cytokine profile for clinical success (33).…”

A Randomized, Double-Blind, Placebo-Controlled Trial Assessing the Oral Administration of a Heat-Treated <b><i>Lactobacillus paracasei </i></b>Supplement in Infants with Atopic Dermatitis Receiving Topical Corticosteroid Therapy

“…The rationale for this approach is based on the well-recognized effects of specific probiotics on cellular immune responses [6]. As part of the “hygiene hypothesis” it is speculated that the recent rise in allergic diseases may be linked to fewer bacterial encounters in progressively cleaner environments, with a substantial effect on the mucosal immunity conferred in part by the normal intestinal microbial flora [7].…”

Years in Review: Recent Progress in Cellular Allergology

“…Nevertheless, these data clearly show that the detrimental effects of disturbed barrier function can be counteracted by dietary GOS supplementation and that a reduction of IL-33 levels seems to be critically involved in this protective effect. A more direct approach was taken by Holvoet et al [7] who cocultured human T cells, skewed towards the Th2 phenotype by a classic protocol in a 3-day culture with IL-4 and anti-CD40 mAbs [8], with a collection of 35 different probiotic bacterial strains and analyzed the secretion levels of signature cytokines. Of note, all strains downregulated IL-5 secretion levels similarly to or even stronger than LPS, which was used as a control.…”

“…Besides simply modulating cytokine profiles, it cannot be excluded that probiotics might also be involved in the reinforcement of the intestinal barrier, which would, however, require alternative tests for accurate evaluation. Nevertheless, the established in vitro assay allows the preselection of probiotics revealing a potentially beneficial cytokine pattern as candidates for detailed in vivo evaluations in the future [7]. …”