title: Pre- and postnatal administration of Lactobacillus reuteri decreases TLR2 responses in infants.
abstract: BACKGROUND
  Mice models indicate that intact Toll like receptor (TLR) signaling may be essential for the allergy protective effects of diverse bacterial exposure observed in clinical trials and epidemiological studies. Probiotic supplementation with Lactobacillus reuteri from pregnancy week 36 and to the infant through the first year of life decreased the prevalence of IgE-associated eczema at two years (ClinicalTrials.gov NCT01285830). The effect of this supplementation on innate immune responses to bacterial products and the expression of associated TLRs were explored.
  
  
  METHODS
  Blood mononuclear cells were collected at birth, 6, 12 and 24 months from 61 infants and cultured with TLR2, 4 and 9 ligands. Cytokine and chemokine secretion was determined as well as TLR2, 4 and 9 mRNA expression.
  
  
  RESULTS
  Probiotic supplementation was associated with decreased LTA (lipoteichoic acid) induced CCL4, CXCL8, IL-1β and IL-6 responses at 12 months and decreased CCL4 and IL-1β secretion at 24 months. TLR2 mRNA expression was not affected by probiotic treatment.
  
  
  CONCLUSIONS
  Decreased responses to TLR2, the main receptor for LTA from Gram positive bacteria, in probiotic treated children seem to be dependent on factors downstream of TLR mRNA expression.
authors.affiliation: Department of Clinical and Experimental Medicine, Unit of Autoimmunity and Immune Regulation, Division of Clinical Immunology, Linköping University, SE-581 85 Linköping, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Forsberg
authors.affiliation: Department of Clinical and Experimental Medicine, Division of Pediatrics, Linköping University, Linköping, Sweden.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Abrahamsson
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, Solna, Stockholm, Sweden ; School of Health and Medical Sciences, Örebro University, Örebro, Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Björkstén
authors.affiliation: Department of Clinical and Experimental Medicine, Unit of Autoimmunity and Immune Regulation, Division of Clinical Immunology, Linköping University, SE-581 85 Linköping, Sweden.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Jenmalm
keywords: Allergy; Chemokine; Cytokine; Eczema; Infancy; Lactobacillus reuteri; Probiotics; Sensitization; TLR