title: Differential expression of ovine innate immune genes by preterm and neonatal lung epithelia infected with respiratory syncytial virus.
abstract: Preterm infants have increased susceptibility to severe manifestations of respiratory syncytial virus (RSV) infection. The cause(s) for this age-dependent vulnerability is/are not well-defined, but alterations in innate immune products have been implicated. In sheep, RSV disease severity has similar age-dependent characteristics and sheep have several related innate molecules for study during pulmonary infection including surfactant protein A (SP-A), surfactant protein D (SP-D), sheep beta defensin 1 (SBD1), monocyte chemotactic protein 1 (MCP1), and Toll-like receptor 4 (TLR4). However, the in vivo cellular gene expression as a response to RSV infection is poorly understood. In this study, the effect of RSV infection on expression of these innate immune genes was determined for bovine RSV-infected (bRSV+ fluorescence) epithelial cells, adjacent cells lacking bRSV antigen (adjoining cells lacking fluorescence), and control cells from non-infected lung using laser capture microdissection (LCM) and real-time RT-PCR. Control lambs had increased expression of innate immune molecules in full term (term) compared to preterm epithelia with statistical significance in SBD1, SP-D, and TLR4 mRNA. Infected cells (bRSV+ fluorescent cells) had consistently higher mRNA levels of SP-A (preterm and term), MCP1 (preterm and term), and SP-D (preterm). Interestingly, bRSV- cells of infected term lambs had significantly reduced SP-D mRNA expression compared to bRSV+ and control epithelia, suggesting that RSV infected cells may regulate the adjacent epithelial SP-D expression. This study defines specific innate immune components (e.g., SBD1, SP-D, and TLR4) that have differential age-dependent expression in the airway epithelia. Furthermore, cellular bRSV infection enhanced certain innate immune components while suppressing adjacent cellular SP-D expression in term animals. These in vivo gene expression results provide a framework for future studies on age-dependent susceptibility to RSV and RSV pathogenesis.
authors.affiliation: Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University Ames, Iowa 50011-1250, USA.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawashima
authors.forename: David K
authors.initials: DK
authors.lastname: Meyerholz
authors.forename: Jack M
authors.initials: JM
authors.lastname: Gallup
authors.forename: Branka
authors.initials: B
authors.lastname: Grubor
authors.forename: Tatjana
authors.initials: T
authors.lastname: Lazic
authors.forename: Howard D
authors.initials: HD
authors.lastname: Lehmkuhl
authors.forename: Mark R
authors.initials: MR
authors.lastname: Ackermann
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism / Q000821:virology; D018507:Gene Expression Regulation, Developmental; D007113:Immunity, Innate / Q000235:genetics*; D007834:Lasers; D008168:Lung / Q000166:cytology / Q000821:virology*; D042282:Microdissection / Q000379:methods; D047928:Premature Birth / Q000662:veterinary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology / Q000662:veterinary / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000472:pathogenicity*; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology* / Q000821:virology
chemical_list: D012333:RNA, Messenger