title: Reduced inflammation and altered innate response in neonates during paramyxoviral infection.
abstract: BACKGROUND
  Human infants are frequently hospitalized due to infection with the paramyxovirus respiratory syncytial virus (RSV). However, very little is known about the neonatal response to paramyxoviral infection. Here, a neonatal model of paramyxoviral infection is developed using the mouse pathogen Sendai virus (SeV).
  
  
  RESULTS
  Adult mice infected with SeV developed a predominantly neutrophilic inflammatory cell influx and a concomitant reduction in lung function, as determined by oxygen saturation. In contrast, neonates with SeV had significantly reduced inflammation and normal lung function. Surprisingly, infected neonates had similar viral loads as adult mice. A reduced neutrophil influx in the neonates may be due in part to reduced expression of both CXCL2 and intracellular adhesion molecule-1 (ICAM-1). Expression of IFN-γ and TNF-α increased in a dose-dependent manner in adult lungs, but neonates did not increase expression of either of these cytokines, even at the highest doses. Importantly, the expression of the RIG-I-like receptors (RLRs) was delayed in the neonatal mice, which might have contributed to their reduced inflammation and differential cytokine expression.
  
  
  CONCLUSIONS
  Neonatal mice developed similar SeV titers and cleared the virus with similar efficiency despite developing a dramatically lower degree of pulmonary inflammation compared to adults. This suggests that inflammation in the lung may not be required to control viral replication. Future studies will be needed to determine any effect the reduced inflammation may have on the development of a protective memory response in neonates.
authors.affiliation: Department of Biology, Saint Louis University, 3507 Laclede Avenue, Saint Louis, MO 63103, USA.
authors.forename: Somashubhra
authors.initials: S
authors.lastname: Bhattacharya
authors.forename: Brandon T
authors.initials: BT
authors.lastname: Beal
authors.forename: Ann M
authors.initials: AM
authors.lastname: Janowski
authors.forename: Laurie P
authors.initials: LP
authors.lastname: Shornick
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D000831:Animals, Newborn / Q000276:immunology; D001835:Body Weight; D004195:Disease Models, Animal; D006801:Humans; D007113:Immunity, Innate; D007223:Infant; D007249:Inflammation / Q000276:immunology / Q000503:physiopathology*; D008168:Lung / Q000276:immunology / Q000821:virology; D051379:Mice; D008810:Mice, Inbred C57BL; D012129:Respiratory Function Tests; D010253:Respirovirus Infections / Q000276:immunology* / Q000503:physiopathology* / Q000821:virology; D029082:Sendai virus / Q000276:immunology / Q000472:pathogenicity* / Q000502:physiology; D019562:Viral Load