A Lactobacillus rhamnosus Strain Induces a Heme Oxygenase Dependent Increase in Foxp3+ Regulatory T Cells |
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| Authors: | Khalil Karimi Nalaayini Kandiah Jessie Chau John Bienenstock Paul Forsythe |
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| Institution: | 1. The Brain Body institute, McMaster University, Hamilton, Ontario, Canada.; 2. Firestone Institute for Respiratory Health, McMaster University, Hamilton, Ontario, Canada.; 3. Department of Medicine, McMaster University, Hamilton, Ontario, Canada.; 4. Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.; McGill University Health Center, Canada, |
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| Abstract: | We investigated the consequences of feeding with a Lactobacillus species on the immune environment in GALT, and the role of dendritic cells and heme oxygenase-1 in mediating these responses. Feeding with a specific strain of Lactobacillus rhamnosus induced a significant increase in CD4+CD25+Foxp3+ functional regulatory T cells in GALT. This increase was greatest in the mesenteric lymph nodes and associated with a marked decrease in TNF and IFNγ production. Dendritic cell regulatory function and HO-1 expression was also increased. The increase in Foxp3+ T cells could be prevented by treatment with a heme oxygenase inhibitor. However, neither inhibition of heme oxygenase nor blockade of IL-10 and TGFβ prevented the inhibition of inflammatory cytokine production. In conclusion Lactobacillus feeding induced a tolerogenic environment in GALT. HO-1 was critical to the enhancement of Foxp3+ regulatory T cells while additional, as yet unknown, pathways were involved in the down-regulation of inflammatory cytokine production by T cells. |
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