Neonatal immune responses to TLR2 stimulation: influence of maternal atopy on Foxp3 and IL-10 expression.
BACKGROUND
Maternal atopic background and stimulation of the adaptive immune system with allergen interact in the development of allergic disease. Stimulation of the innate immune system through microbial exposure, such as activation of the innate Toll-like-receptor 2 (TLR2), may reduce the development of allergy in childhood. However, little is known about the immunological effects of microbial stimulation on early immune responses and in association with maternal atopy.


METHODS
We analyzed immune responses of cord blood mononuclear cells (CBMC) from 50 healthy neonates (31 non-atopic and 19 atopic mothers). Cells were stimulated with the TLR2 agonist peptidoglycan (Ppg) or the allergen house dust mite Dermatophagoides farinae (Derf1), and results compared to unstimulated cells. We analyzed lymphocyte proliferation and cytokine secretion of CBMC. In addition, we assessed gene expression associated with T regulatory cells including the transcription factor Foxp3, the glucocorticoid-induced TNF receptor (GITR), and the cytotoxic lymphocyte antigen 4 (CTLA4). Lymphocyte proliferation was measured by 3H-Thymidine uptake, cytokine concentrations determined by ELISA, mRNA expression of T cell markers by real-time RT-PCR.


RESULTS
Ppg stimulation induced primarily IL-10 cytokine production, in addition to IFN-gamma, IL-13 and TNF-alpha secretion. GITR was increased following Ppg stimulation (p = 0.07). Ppg-induced IL-10 production and induction of Foxp3 were higher in CBMC without, than with maternal atopy (p = 0.04, p = 0.049). IL-10 production was highly correlated with increased expression of Foxp3 (r = 0.53, p = 0.001), GITR (r = 0.47, p = 0.004) and CTLA4 (r = 0.49, p = 0.003), independent of maternal atopy.


CONCLUSIONS
TLR2 stimulation with Ppg induces IL-10 and genes associated with T regulatory cells, influenced by maternal atopy. Increased IL-10 and Foxp3 induction in CBMC of non-atopic compared to atopic mothers, may indicate an increased capacity to respond to microbial stimuli.
University Children's Hospital Munich, Department of Pulmonary, LMU, Munich, Germany. Bianca.Schaub@med.uni-muenchen.de
Bianca
B
Schaub
Monica
M
Campo
Hongzhen
H
He
David
D
Perkins
Matthew W
MW
Gillman
Diane R
DR
Gold
Scott
S
Weiss
Ellice
E
Lieberman
Patricia W
PW
Finn
D000485:Allergens; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics; D060908:CTLA-4 Antigen; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D051858:Forkhead Transcription Factors / Q000235:genetics*; D053450:Glucocorticoid-Induced TNFR-Related Protein; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D007231:Infant, Newborn; D016753:Interleukin-10 / Q000235:genetics*; D008213:Lymphocyte Activation; D008431:Maternal-Fetal Exchange; D010457:Peptidoglycan / Q000494:pharmacology*; D011247:Pregnancy; D039981:Pyroglyphidae / Q000276:immunology*; D017475:Receptors, Nerve Growth Factor / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics; D051195:Toll-Like Receptor 2 / Q000502:physiology*
D000485:Allergens; D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053450:Glucocorticoid-Induced TNFR-Related Protein; D010457:Peptidoglycan; D017475:Receptors, Nerve Growth Factor; D018124:Receptors, Tumor Necrosis Factor; C495342:TLR2 protein, human; C491405:TNFRSF18 protein, human; D051195:Toll-Like Receptor 2; D016753:Interleukin-10