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An influx of macrophages is the predominant local immune response in ovine pulmonary adenocarcinoma

Citation

Summers, C and Norval, M and De las Heras, M and Gonzalez, L and Sharp, JM and Woods, GM, An influx of macrophages is the predominant local immune response in ovine pulmonary adenocarcinoma, Veterinary Immunology and Immunopathology, 106, (3-4) pp. 285-294. ISSN 0165-2427 (2005) [Refereed Article]

DOI: doi:10.1016/j.vetimm.2005.03.006

Abstract

Infection with a retrovirus, Jaagsiekte sheep retrovirus (JSRV), causes ovine pulmonary adenocarcinoma (OPA). The excess production of surfactant proteins by alveolar tumour cells results in increased production of pulmonary fluid, which is characteristically expelled through the nostrils of affected sheep. The immune response to JSRV and the tumour is poorly understood: no JSRV-specific circulating antibodies or T cells have been detected to date. The aim of the present study was to obtain phenotypic evidence for a local immune response in OPA lungs. Specific-pathogen free lambs were infected intratracheally with JSRV. When clinical signs of OPA were apparent, the lungs were removed at necropsy and immunohistochemistry (IHC) was performed on lung sections using a panel of mouse anti-sheep mAbs. No influx of dendritic cells, B cells, CD4, CD8 or γδ T cells was seen in the neoplastic nodules or in their periphery. MHC Class II-positive cells were found intratumourally, peritumourally and in the surrounding alveolar lumina. In the tumours, many of these cells were shown to be fibroblasts and the remainder were likely to be mature macrophages. In the alveolar lumen, the MHC Class II-positive cells were CD14-positive and expressed high levels of IFN-γ. They appeared to be immature monocytes or macrophages which then differentiated to become CD14-negative as they reached the periphery of the tumours. A high level of MHC Class I expression was detected on a range of cells in the OPA lungs but the tumour nodules themselves contained no MHC Class I-positive cells. On the basis of these findings, it is proposed that the lack of an effective immune response in OPA could result from a mechanism of peripheral tolerance in which the activity of the invading macrophages is suppressed by the local environment, possibly as a consequence of the inhibitory properties of the surfactant proteins. © 2005 Elsevier B.V. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Agricultural and Veterinary Sciences
Research Group:Veterinary Sciences
Research Field:Veterinary Immunology
Objective Division:Animal Production and Animal Primary Products
Objective Group:Livestock Raising
Objective Field:Sheep - Meat
Author:Woods, GM (Professor Gregory Woods)
ID Code:34068
Year Published:2005
Web of Science® Times Cited:18
Deposited By:Pathology
Deposited On:2005-08-01
Last Modified:2006-06-07
Downloads:0

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