Immunohistochemical evaluation of IFN-γ levels in sheep verminous pneumonia

Abstract

Lungworms, a group of parasitic nematodes, are recognized as one of the major and most common parasitic pneumonia agents in ruminants worldwide. In this study, the expressions of interferon gamma (IFN-γ), which is an important pro-inflammatory cytokine, were evaluated by immunohistochemical methods in order to evaluate the immune response against parasitic agents in sheep naturally infected with different types of lungworms. The material for this study consisted of lung tissue samples obtained from 40 dead sheep brought for routine histopathological diagnosis to the Department of Pathology. In order to reveal the histopathological changes in the tissues, Hematoxylin and Eosin (H&E) staining was applied to the sections. Lung tissues were stained with IFN-γ commercial antibody using the Avidin-Biotin Peroxidase Technique (ABC) following the procedures of the manufacturer. Subpleural multifocal nodules of several mm in diameter were detected in the dorsal regions of the lung, especially in the caudal lobes. In the histopathological examination of the lungs, it was observed that the alveoli, bronchi, and bronchiole lumens were filled with adult forms, larvae, and eggs of the parasitic agents. Compared to the control group, the expressions of IFN-γ were significantly increased in the verminous pneumonia group. Overall, the study suggests that the Th1 response, as represented by increased IFN-γ expression, appears to play an active role in the immunity developed against lungworms in ruminants.