A Lactobacillus rhamnosus strain induces a heme oxygenase dependent increase in Foxp3+ regulatory T cells.
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.
The Brain Body institute, McMaster University, Hamilton, Ontario, Canada. karimik@mcmaster.ca
Khalil
K
Karimi
Nalaayini
N
Kandiah
Jessie
J
Chau
John
J
Bienenstock
Paul
P
Forsythe
D000818:Animals; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005786:Gene Expression Regulation; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000378:metabolism; D052201:Lacticaseibacillus rhamnosus / Q000472:pathogenicity*; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic / Q000382:microbiology; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000378:metabolism / Q000382:microbiology
D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D006419:Heme Oxygenase (Decyclizing)