title: Neonatal T-cell maturation and homing receptor responses to Toll-like receptor ligands differ from those of adult naive T cells: relationship to prematurity.
abstract: BACKGROUND
  Inflammation and infection are associated with premature birth and with activation of the fetal immune system. We hypothesized that exposure to microbial Toll-like receptor (TLR) ligands plays an important role in neonatal T-cell maturation and that early exposure to microbial products may result in early T-cell maturation and a tendency for these matured effector cells to change their homing receptor patterns.
  
  
  RESULTS
  Expression of the CD45RO marker was induced in term neonatal T cells after in vitro exposure to TLR ligands for 7 days. Interestingly, naive T cells from adult blood were unaffected by TLR ligand exposure. In addition, neonatal T cells had more cells with decreased expression of the α4β7 integrins and increased expression of CCR4 after in vitro exposure of TLR ligands-similar to the expression of these molecules in adult naive T cells.
  
  
  CONCLUSIONS
  These findings are relevant for the understanding of neonatal T-cell maturation and may contribute to our understanding of multiorgan inflammatory complications of prematurity.
  
  
  METHODS
  Cord blood was obtained from term and preterm infants. Using flow cytometry, we identified a mature (CD45RO(+)) phenotype in preterm infant cord blood (CB) T cells that had decreased expression of the α4β7 integrins and increased expression of the C-C chemokine receptor 4 (CCR4) as compared with term infant CB.
authors.affiliation: Department of Pediatrics, Case Western Reserve School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Maricruz
authors.initials: M
authors.lastname: Crespo
authors.forename: Denise G
authors.initials: DG
authors.lastname: Martinez
authors.forename: Adam
authors.initials: A
authors.lastname: Cerissi
authors.forename: Brenda
authors.initials: B
authors.lastname: Rivera-Reyes
authors.forename: Helene B
authors.initials: HB
authors.lastname: Bernstein
authors.forename: Michael M
authors.initials: MM
authors.lastname: Lederman
authors.forename: Scott F
authors.initials: SF
authors.lastname: Sieg
authors.forename: Angel A
authors.initials: AA
authors.lastname: Luciano
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000276:immunology*; D016022:Case-Control Studies; D002478:Cells, Cultured; D002821:Chorioamnionitis / Q000276:immunology / Q000382:microbiology; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D005434:Flow Cytometry; D005865:Gestational Age; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology; D007156:Immunologic Memory; D016130:Immunophenotyping; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000276:immunology*; D016023:Integrins / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008024:Ligands; D008213:Lymphocyte Activation; D010641:Phenotype; D011247:Pregnancy; D047928:Premature Birth / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D054398:Receptors, CCR4 / Q000378:metabolism; D016201:Receptors, Lymphocyte Homing / Q000187:drug effects / Q000378:metabolism*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D051193:Toll-Like Receptors / Q000819:agonists / Q000378:metabolism*; D014481:United States
chemical_list: C515354:CCR4 protein, human; D007155:Immunologic Factors; D016023:Integrins; D008024:Ligands; D054398:Receptors, CCR4; D016201:Receptors, Lymphocyte Homing; D051193:Toll-Like Receptors; C071777:integrin alpha4beta7; D017493:Leukocyte Common Antigens