Lactobacillus reuteri–induced Regulatory T cells Protect against an Allergic Airway Response in Mice

TLDR: A role for nonantigen-specific CD4(+)CD25(+)Foxp3(+) regulatory T cells in attenuating the allergic airway response following oral treatment with L. reuteri is found and may have therapeutic potential in controlling the Th2 bias observed in atopic individuals.

Abstract: Rationale: We have previously demonstrated that oral treatment with live Lactobacillus reuteri can attenuate major characteristics of the asthmatic response in a mouse model of allergic airway inflammation. However, the mechanisms underlying these effects remain to be determined.Objectives: We tested the hypothesis that regulatory T cells play a major role in mediating L. reuteri–induced attenuation of the allergic airway response.Methods: BALB/c mice were treated daily with L. reuteri by gavage. Flourescent-activated cell sorter analysis was used to determine CD4+CD25+Foxp3+T cell populations in spleens following treatment with L. reuteri or vehicle control. Cell proliferation assays were performed on immunomagnetic bead separated CD4+CD25+ and CD4+CD25− T cells. CD4+CD25+ T cells isolated from, ovalbumin naive, L. reuteri treated mice were transferred into ovalbumin-sensitized mice. Following antigen challenge the airway responsiveness, inflammatory cell influx and cytokine levels in bronchoalveolar lav...