title: The difference in immune response and IL-12p35 methylation between newborns and adults.
abstract: BACKGROUND
  The immune system of newborn is generally depressed by impaired production of Th1-cell associated cytokines, which results in increased susceptibility to intracellular pathogens and poor response to vaccinations. For avoiding abortion, the maternal and fetal immune systems tend to Th2-cell polarizing cytokines. Besides, IL-12p35 is a determining factor of the bioactivity of IL-12, which has an important role in the Th1 response. Recently methylated DNA is known to associate to inhibit transcription. Therefore, we explored the methylation status of CpG sites upstream of the coding sequence of the IL-12p35 gene to determine whether neonatal peripheral blood mononuclear cell (PBMC) synthesis lower level of IL-12 is related to methylated DNA.
  
  
  RESULTS
  PBMCs from adults expressed higher levels of IL-12p40 (p = 0.303) and IL-12p70 (p = 0.045) and had a strong ability to produce IL-12p35 mRNA (p = 0.01). However, there was no difference in the methylation status of CpG sites in the promoter of IL-12p35 between adults and newborns.
  
  
  CONCLUSIONS
  We found that PBMC synthesis of bioactive IL-12p70 was significantly impaired in the neonatal period, potentially though a reduction in IL-12p35 production. The reeducation in IL-12p35 production might not be due to methylation of the promoter gene. But, the impairment of IL-12p35 expression during the neonatal period might be caused by other epigenetic regulation occurs in the chromatin level.
authors.forename: Chia-Jung
authors.initials: CJ
authors.lastname: Chen
authors.forename: Jia-Woei
authors.initials: JW
authors.lastname: Hou
authors.affiliation: Graduate Institute of Immunology, National Taiwan University, No, 7 Chung-Shan South Road, Taipei 100, Taiwan. gicmbor@ntu.edu.tw.
authors.forename: Bor-Luen
authors.initials: BL
authors.lastname: Chiang
mesh_terms: D000328:Adult; D000375:Aging / Q000235:genetics / Q000276:immunology*; D002843:Chromatin / Q000235:genetics / Q000276:immunology; D018899:CpG Islands / Q000276:immunology*; D019175:DNA Methylation / Q000235:genetics / Q000276:immunology*; D044127:Epigenesis, Genetic / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D053765:Interleukin-12 Subunit p35 / Q000235:genetics / Q000276:immunology*; D008297:Male; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology*; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology*
chemical_list: D002843:Chromatin; C508858:IL12A protein, human; D053765:Interleukin-12 Subunit p35