Expression of pentraxin 3 in the lungs of human, horse, cattle and pig

Abstract

Bacterial lung diseases cause significant mortality and morbidity, causing enormous economic damage to the animal industry and cost billions of dollars in human health care. The innate immune system plays a critical role in the initiation of immune response in the lung. Pentraxin 3 (PTX3) is an acute phase protein that is produced at sites of inflammation by many cell types upon stimulation by proinflammatory cytokines, and agonists such as endotoxins. PTX3 recognizes and binds to many pathogens, activates the complement cascade, and has a role in the clearance of apoptotic and necrotic cells. Because there are very few data on the expression of PTX3 in the lungs, we examined PTX3 expression in normal and inflamed lungs of the horse, pig, human, and cattle using light and electron microscopic immunochemistry. We show PTX3 staining in bronchial epithelial cells and vascular endothelium in normal and inflamed lungs. Alveolar macrophages and inflammatory cells recruited into the lungs of bacteria‐infected animals stain intensely for PTX3. Immuno‐gold electron microscopy on horse, and calf lungs showed PTX3 in the nuclei, cytoplasm, and vesicular organelles of alveolar macrophages, endothelial cells and pulmonary intravascular macrophages. These data show PTX3 is expressed in normal lungs and its expression is increased in inflamed lungs.Grant Funding Source: Alberta Livestock and Meat Agency