Sheep pox virus induces proliferation of type II pneumocytes in the lungs.
The present study investigated the expression of pulmonary surfactant proteins (surfactant protein [SP]-A, SP-B, proSP-C), thyroid transcription factor-1 (TTF-1), proliferating cell nuclear antigen (PCNA) and the infiltration of CD3(+) T and CD79alphacy(+) B lymphocytes into the lungs of 10 lambs naturally infected with sheep pox virus. Microscopical examination detected marked epithelial hyperplasia, sheep pox cells and neutrophilic infiltration in pock nodules. Immunohistochemistry demonstrated intense expression of SPs in the cytoplasm of the hyperplastic type II pneumocytes in the nodular pock lesions. These cells displayed a gland-like arrangement. The hyperplastic and the normal bronchiolar epithelium did not express SPs. The nuclei of the hyperplastic and normal type II pneumocytes labelled positively for TTF-1. Strong PCNA positivity indicated epithelial cell proliferation in the pock nodules. Moderate to abundant numbers of CD3(+) T cells, but few CD79alphacy B lymphocytes, were detected in the pock lesions. Transmission electron microscopy revealed that the hyperplasia in the pock nodules comprised predominantly type II pneumocytes and that the sheep pox cells and epithelial cells contained virus particles in their cytoplasm. The results of this study show that sheep pox virus induces marked proliferation of type II pneumocytes and bronchiolar epithelial cells and that the lung lesions in diseased lambs are mainly proliferative.
Beytut
E
E
Department of Pathology, Faculty of Veterinary Medicine, University of Kafkas, Kars, Turkey. enverbeytut@hotmail.com
D056809:Alveolar Epithelial Cells / Q000473:pathology* / Q000821:virology; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D001980:Bronchi / Q000473:pathology / Q000821:virology; D017252:CD3 Complex / Q000096:biosynthesis; D051925:CD79 Antigens / Q000096:biosynthesis; D018151:Capripoxvirus; D049109:Cell Proliferation; D007150:Immunohistochemistry; D008168:Lung / Q000378:metabolism / Q000473:pathology*; D009687:Nuclear Proteins / Q000378:metabolism; D011213:Poxviridae Infections / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D037661:Pulmonary Surfactant-Associated Proteins / Q000378:metabolism; D011663:Pulmonary Surfactants; D020545:Respiratory Mucosa / Q000473:pathology / Q000821:virology; D012756:Sheep; D012757:Sheep Diseases / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism
D017252:CD3 Complex; D051925:CD79 Antigens; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors