Immunohistochemical demonstration of Toll Like Receptors - 2, 4 and 6 in mycoplasmal pneumonia

Abstract

Mycoplasmal pneumonia is a highly contagious disease that causes serious economic losses in sheep, goats, and cattle worldwide. The aim of this study was to investigate the pathomorphological findings and the immunohistochemical distribution of Toll-Like Receptors (TLRs) involved in the pathogenesis of mycoplasmal pneumonia (n=40). Histopathological examination revealed, purulent bronchopneumonia (n=13), fibrinous bronchopneumonia (n=14), interstitial pneumonia (n=6), granulomatous pneumonia (n=1), and non-specific lesions (n=6). The same tissue sections were immunohistochemically stained with antibodies against Mycoplasma pneumoniae, TLR-2, TLR-4, and TLR-6. Immunopositivity for TLRs was observed in bronchial, bronchiolar, alveolar epithelial cells and inflammatory cells. Although no statistically significant difference was found between the groups, TLR-2-positive cell counts were numerically higher in purulent inflammation, whereas TLR-4-positive cell counts were numerically higher in fibrinous inflammation. The results indicate that TLR-2, TLR-4, and TLR-6 may contribute to the inflammatory response in mycoplasmal pneumonia.