Histopathological and Immunohistochemical Findings in the Lungs of Pigs Infected Experimentally with Mycoplasma hyopneumoniae

Abstract

Pigs were infected intranasally with Mycoplasma hyopneumoniae and killed at. intervals ranging from 7 to 35 days post-infection (dpi). Histopathological changes consisted of (1) exudates airways and alveolar lumina, (2) peribronchial and peribronchiolar lymphoid hyperplasia, and (3) enlargement of alveolar septa. These changes were particularly marked from 7 to 28 dpi, coinciding with significant increases in the expression, detected immunohistochemically, of cytokines (IL-1 alpha, IL-1 beta, IL-8, TNF-alpha and INF-gamma) and lymphoid markers (CD4+ CD8 +, muramidase, IgG +, IgA+). Both the lesions and immunohistochemical signals declined in intensity, beyond 35 days. (C) 2009 Elsevier Ltd. All rights reserved.