Immune response to intrapharyngeal LPS in neonatal and juvenile mice

Research output: Contribution to journalArticle


Neonates and infants have a higher morbidity and mortality associated with lower respiratory tract illnesses compared with older children. To identify age-related and longitudinal differences in the cellular immune response to acute lung injury (ALI), neonatal and juvenile mice were given Escherichia coli LPS using a novel, minimally invasive aspiration technique. Neonatal and juvenile mice received between 3.75 and 7.5 mg/kg LPS by intrapharyngeal aspiration. Airway and lung cells were isolated and characterized by flow cytometry, cytokine/chemokine mRNA expression from lung homogenates was quantified, and lung morphometry and injury scores were performed. LPS-treated neonatal mice underwent adoptive transfer with adult T regulatory cells (Tregs). After LPS aspiration, lung monocytes isolated from neonatal mice had a predominant M2 phenotype, whereas lung monocytes from juvenile mice displayed a mixed M1/M2 phenotype. At 72 hours after LPS exposure, neonatal lungs were slower to resolve inflammation and expressed lower mRNA levels of CCL2, CCL5, CXCL10, and IL-10. Juvenile, but not neonatal, mice demonstrated a significant increase in airway Tregs after LPS exposure. Adoptive transfer of adult Tregs into LPS-challenged neonatal mice resulted in reduced lung inflammation and improved weight gain. These findings underscore several vulnerabilities in the neonatal immune response to LPS-induced ALI. Most striking was the deficiency in airway Tregs after LPS aspiration. Adoptive transfer of adult Tregs mitigated LPS-induced ALI in neonatal mice, highlighting the importance of age-related differences in Tregs and their response to ALI during early postnatal development.

Original languageEnglish (US)
Pages (from-to)323-331
Number of pages9
JournalAmerican journal of respiratory cell and molecular biology
Issue number3
StatePublished - Mar 1 2015


  • Acute lung injury
  • Escherichia coli LPS
  • Juvenile
  • Neonate

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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