Enhanced surfactant protein and defensin mRNA levels and reduced viral replication during parainfluenza virus type 3 pneumonia in neonatal lambs.
Defensins and surfactant protein A (SP-A) and SP-D are antimicrobial components of the pulmonary innate immune system. The purpose of this study was to determine the extent to which parainfluenza type 3 virus infection in neonatal lambs alters expression of sheep beta-defensin 1 (SBD-1), SP-A, and SP-D, all of which are constitutively transcribed by respiratory epithelia. Parainfluenza type 3 viral antigen was detected by immunohistochemistry (IHC) in the bronchioles of all infected lambs 3 days postinoculation and at diminished levels 6 days postinoculation, but it was absent 17 days postinoculation. At all times postinoculation, lung homogenates from parainfluenza type 3 virus-inoculated animals had increased SBD-1, SP-A, and SP-D mRNA levels as detected by fluorogenic real-time reverse transcriptase PCR. Protein levels of SP-A in lung homogenates detected by quantitative-competitive enzyme-linked immunosorbent assay and protein antigen of SP-A detected by IHC were not altered. These studies demonstrate that parainfluenza type 3 virus infection results in enhanced expression of constitutively transcribed innate immune factors expressed by respiratory epithelia and that this increased expression occurs concurrently with decreased viral replication.
Grubor
Branka
B
Department of Veterinary Pathology, 2740 Veterinary Medicine, Iowa State University, Ames, IA 50011-1250, USA. brankag@iastate.edu
Gallup
Jack M
JM
Meyerholz
David K
DK
Crouch
Erika C
EC
Evans
Richard B
RB
Brogden
Kim A
KA
Lehmkuhl
Howard D
HD
Ackermann
Mark R
MR
D000818:Animals; D000831:Animals, Newborn; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000032:analysis / Q000276:immunology; D001831:Body Temperature; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000737:chemistry / Q000821:virology; D005260:Female; D015870:Gene Expression; D007150:Immunohistochemistry; D008168:Lung / Q000737:chemistry / Q000473:pathology / Q000821:virology; D016676:Macrophages, Alveolar / Q000737:chemistry / Q000821:virology; D008297:Male; D018184:Paramyxoviridae Infections / Q000235:genetics / Q000276:immunology* / Q000662:veterinary; D011014:Pneumonia / Q000235:genetics / Q000276:immunology* / Q000662:veterinary; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics* / Q000378:metabolism; D037663:Pulmonary Surfactant-Associated Protein D / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D018108:Respirovirus / Q000737:chemistry / Q000254:growth & development / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012756:Sheep; D012757:Sheep Diseases / Q000235:genetics / Q000276:immunology / Q000821:virology; D014779:Virus Replication; D023083:beta-Defensins / Q000235:genetics*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D012333:RNA, Messenger; D023083:beta-Defensins