Early life exposure to lipopolysaccharide suppresses experimental autoimmune encephalomyelitis by promoting tolerogenic dendritic cells and regulatory T cells.
The rising incidence of autoimmune diseases such as multiple sclerosis (MS) in developed countries might be due to a more hygienic environment, particularly during early life. To investigate this concept, we developed a model of neonatal exposure to a common pathogen-associated molecular pattern, LPS, and determined its impact on experimental autoimmune encephalomyelitis (EAE). Mice exposed to LPS at 2 wk of age showed a delayed onset and diminished severity of myelin oligodendrocyte glycoprotein (MOG)-induced EAE, induced at 12 wk, compared with vehicle-exposed animals. Spinal cord transcript levels of CD3epsilon and F4/80 were lower in LPS- compared with PBS-exposed EAE animals with increased IL-10 levels in the LPS-exposed group. Splenic CD11c(+) cells from LPS-exposed animals exhibited reduced MHC class II and CD83 expression but increased levels of CD80 and CD86 both before and during EAE. MOG-treated APC from LPS-exposed animals stimulated less T lymphocyte proliferation but increased expansion of CD4(+)FoxP3(+) T cells compared with APC from PBS-exposed animals. Neuropathological studies disclosed reduced myelin and axonal loss in spinal cords from LPS-exposed compared with PBS-exposed animals with EAE, and this neuroprotective effect was associated with an increased number of CD3(+)FoxP3(+) immunoreactive cells. Analyses of human brain tissue revealed that FoxP3 expression was detected in lymphocytes, albeit reduced in MS compared with non-MS patients' brains. These findings support the concept of early-life microbial exposure influencing the generation of neuroprotective regulatory T cells and may provide insights into new immunotherapeutic strategies for MS.
Ellestad
Kristofor K
KK
Department of Medicine, University of Alberta, Edmonton, Canada.
Tsutsui
Shigeki
S
Noorbakhsh
Farshid
F
Warren
Kenneth G
KG
Yong
V Wee
VW
Pittman
Quentin J
QJ
Power
Christopher
C
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology*; D002465:Cell Movement / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D005260:Female; D051858:Forkhead Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D007108:Immune Tolerance / Q000235:genetics; D016753:Interleukin-10 / Q000096:biosynthesis / Q000235:genetics; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D051379:Mice; D008810:Mice, Inbred C57BL; D009103:Multiple Sclerosis / Q000276:immunology / Q000378:metabolism; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D012720:Severity of Illness Index; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism / Q000473:pathology
D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D008070:Lipopolysaccharides; D018696:Neuroprotective Agents; D016753:Interleukin-10