Table 2.
Microscopic lesions and distribution of AI nucleoprotein antigen in tissues by immunohistochemistry
| Tissuea | Commercial broiler | SPF layer | Viral antigen stained cell types | Type of lesion | ||
|---|---|---|---|---|---|---|
| 5w | 8w | >30w | 4wb | |||
| Trachea | + | + | − | ++ | Pseudostratified epithelial cells | Focal necrosis with mild lymphoplasmacytic inflammatory infiltrate |
| Lung | +++ | +++ | + | +++ | Epithelium of air capillaries, mononuclear cells, endothelial cells | Moderate congestion, necrosis, and monocyte inflammatory infiltrate |
| Duodenum | + | − | − | na | Macrophages | NSL |
| Cecal tonsils | + | − | − | + | Epithelial cells of villus, cells of the muscularis externa, macrophages | Focal necrosis with lymphoplasmacytic inflammatory infiltrate |
| Pancreas | +++ | ++ | +++ | ++ | Acinar cells | Mild degeneration of individual pancreatic acinar cells |
| Liver | + | + | + | + | Kupffer cells, hepatocytes, macrophages | Focal necrosis with lymphoplasmacytic inflammatory infiltrate, perivascular cuffing |
| Kidney | ++ | +++ | ++ | + | Tubular epithelial cells | Focal necrosis of tubular epithelium with lymphoplasmacytic inflammatory |
| Adrenal gland | ++ | +++ | ++ | ++ | Corticotropic cells | Multifocal areas of necrosis with mononuclear inflammatory infiltrate |
| Spleen | +++ | ++ | +++ | ++ | Mononuclear cells | Multifocal areas of necrosis, hemorrhages, depletion white pulp |
| Thymus | + | + | + | ++ | Mononuclear cells | Focal necrosis, mild lymphocyte depletion, apoptotic lymphocytes |
| Heart | +++ | +++ | +++ | +++ | Myocardiocytes | Multifocal necrosis of myocardiocytes |
| Skeletal muscle | + | ++ | + | na | Myocytes, connective tissue, endothelial cells | NSL |
| Brain | +++ | +++ | +++ | +++ | Neurons, Purkinje cells, ependymal cells, glial cells | Malacia in cortex, necrosis of ependymal cells of ventricles and epithelial cells of choroid plexus, chromatolysis of Purkinje cells, lymphoplasmacytic infiltrate |
| Ovaries | na | na | +++ | na | Tegument/interstitial tissue, granulocytes | Focal necrosis with lymphoplasmacytic inflammatory infiltrate |
| Infundibulum | na | na | + | na | Ciliated epithelial cells | NSL |
4w: 4-week old SPF White Leghorn layers, 5w: 5-week old broilers, 8w: 8-week old broilers, na: not applicable, NSL: no significant lesions.
aTissues not present appeared overtly normal on histopathological analysis and did not show positive immunohistochemical staining.
bFor comparative purposes, data from DeJesus et al. [8] on 4-week old SPF White Leghorn chickens challenged with Tk/MN/15 virus have been added.
− = no positive cells; + = single positive cells; ++ = scattered groups of positive cells; +++ = widespread positivity.