Expression of tumour necrosis factor-alpha is associated with apoptosis in lungs of pigs experimentally infected with porcine reproductive and respiratory syndrome virus.
Expression of tumour necrosis factor (TNF)-alpha and its association with apoptosis was examined in lungs from pig experimentally inoculated with porcine reproductive and respiratory syndrome virus (PRRSV). The TNF-alpha nucleic acid was detected in PRRSV-infected alveolar macrophages by reverse transcription-polymerase chain reaction (RT-PCR). The TNF-alpha antigen was detected in alveolar macrophages by immunohistochemisty. DNA fragmentation in apoptotic cells was detected by in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL). A double-labelling procedure using immunohistochemisty for the detection of PRRSV and the in situ TUNEL assay for the detection of apoptosis demonstrated that a majority of labelled cells were infected with PRRSV or apoptotic, but not both. Apoptotic cells were more abundant than PRRSV-infected cells in all lungs examined. A double-labelling procedure using immunohistochemisty for the detection of TNF-alpha and the in situ TUNEL assay for the detection of apoptosis demonstrated that a majority of labelled cells were apoptotic or for TNF-alpha, but not both. These data suggested that TNF-alpha released from macrophages after infection by PRRSV may induce apoptosis in uninfected bystander cells.
Choi
C
C
Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, Suwon, Republic of Korea.
Chae
C
C
D000818:Animals; D017209:Apoptosis; D005786:Gene Expression Regulation; D020287:In Situ Nick-End Labeling; D008168:Lung / Q000473:pathology* / Q000821:virology*; D016676:Macrophages, Alveolar / Q000378:metabolism / Q000821:virology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000473:pathology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000502:physiology*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D013552:Swine / Q000821:virology*; D013553:Swine Diseases / Q000473:pathology / Q000821:virology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
D012367:RNA, Viral; D014409:Tumor Necrosis Factor-alpha