title: Neonate intestinal immune response to CpG oligodeoxynucleotide stimulation.
abstract: BACKGROUND
  The development of mucosal vaccines is crucial to efficiently control infectious agents for which mucosae are the primary site of entry. Major drawbacks of these protective strategies are the lack of effective mucosal adjuvant. Synthetic oligodeoxynucleotides that contain several unmethylated cytosine-guanine dinucleotide (CpG-ODN) motifs are now recognized as promising adjuvants displaying mucosal adjuvant activity through direct activation of TLR9-expressing cells. However, little is known about the efficacy of these molecules in stimulating the intestinal immune system in neonates.
  
  
  RESULTS
  First, newborn mice received CpG-ODN orally, and the intestinal cytokine and chemokine response was measured. We observed that oral administration of CpG-ODN induces CXC and CC chemokine responses and a cellular infiltration in the intestine of neonates as detected by immunohistochemistry. We next compared the efficiency of the oral route to intraperitoneal administration in stimulating the intestinal immune responses of both adults and neonates. Neonates were more responsive to TLR9-stimulation than adults whatever the CpG-ODN administration route. Their intestinal epithelial cells (IECs) indirectly responded to TLR9 stimulation and contributed to the CXC chemokine response, whereas other TLR9-bearing cells of the lamina-propria produced CC chemokines and Th1-type cytokines. Moreover, we showed that the intestine of adult exhibited a significantly higher level of IL10 at homeostasis than neonates, which might be responsible for the unresponsiveness to TLR9-stimulation, as confirmed by our findings in IL10-deficient mice.
  
  
  CONCLUSIONS
  This is the first report that deciphers the role played by CpG-ODN in the intestine of neonates. This work clearly demonstrates that an intraperitoneal administration of CpG-ODN is more efficient in neonates than in adults to stimulate an intestinal chemokine response due to their lower IL-10 intestinal level. In addition we report the efficiency of the oral route at inducing intestinal chemokine responses in neonate that might be taken into consideration for further vaccine development against neonatal diseases.
authors.affiliation: Laboratoire Contrôle et Immunologie des Maladies Entériques du Nouveau-né, UR1282 Infectiologie Animale et Santé Publique, INRA de Tours, Nouzilly, France. slacroix@tours.inra.fr
authors.forename: Sonia
authors.initials: S
authors.lastname: Lacroix-Lamandé
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rochereau
authors.forename: Roselyne
authors.initials: R
authors.lastname: Mancassola
authors.forename: Mathieu
authors.initials: M
authors.lastname: Barrier
authors.forename: Amandine
authors.initials: A
authors.lastname: Clauzon
authors.forename: Fabrice
authors.initials: F
authors.lastname: Laurent
mesh_terms: D000284:Administration, Oral; D000375:Aging / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D002465:Cell Movement / Q000187:drug effects; D002469:Cell Separation; D018925:Chemokines / Q000378:metabolism; D020895:Enterocytes / Q000166:cytology / Q000187:drug effects; D005260:Female; D007109:Immunity / Q000187:drug effects*; D007249:Inflammation / Q000473:pathology; D007274:Injections, Intraperitoneal; D016753:Interleukin-10 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology; D007422:Intestines / Q000187:drug effects* / Q000276:immunology*; D008198:Lymph Nodes / Q000187:drug effects / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology
chemical_list: C408982:CPG-oligonucleotide; D018925:Chemokines; D009838:Oligodeoxyribonucleotides; D016753:Interleukin-10