Bacterial lung disease caused by Mannheimia haemolytica inflict significant mortality and morbidity resulting in enormous economic losses to cattle industry. The use of antibiotics is becoming more challenging because of development of anti-microbial resistance. The innate immune system plays a critical role in the initiation of immune response in the lung. Pentraxin 3 (PTX3), a pattern-recognition receptor is produced at sites of inflammation by many cell types, 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 lungs of normal and M. haemolytica-infected calves and normal and E. coli lipopolysaccharide-treated cattle neutrophils using light and electron microscopic immunochemistry and Western blots. Immunohistology showed the presence of PTX3 in airway epithelial cells, alveolar septa and macrophages in normal and inflamed lungs of calves and the blots showed a significant increase in the expression of PTX3 in lungs from infected calves. Immuno-gold electron microscopy showed PTX3 in the nuclei, cytoplasm, and vesicular organelles of alveolar macrophages, endothelial cells and pulmonary intravascular macrophages (PIMs). Immunohistochemical staining for PTX3 in peripheral blood neutrophils shows an altered staining pattern in neutrophils stimulated with lipopolysachharide (LPS). However, western blots no significant change in PTX3 amount in LPS-treated neutrophils compared to the controls. These are the first data on the expression of PTX3 in the lungs and the neutrophils of cattle which may add to our understanding of innate immunity in cattle lungs.

由溶血性曼海姆氏菌引起的细菌性肺病造成显着的死亡率和发病率，给养牛业造成巨大的经济损失。由于抗微生物药物耐药性的发展，抗生素的使用变得更具挑战性。先天免疫系统在肺部免疫反应的启动中起着关键作用。Pentraxin 3 (PTX3) 是一种模式识别受体，由多种细胞类型在炎症部位产生，可识别并结合多种病原体，激活补体级联反应，并在清除凋亡和坏死细胞中发挥作用。由于肺中 PTX3 表达的数据很少，我们检查了正常和溶血性支原体感染的小牛以及正常和大肠杆菌使用光和电子显微免疫化学和蛋白质印迹分析脂多糖处理的牛中性粒细胞。免疫组织学显示，在正常和发炎的小牛肺的气道上皮细胞、肺泡隔和巨噬细胞中存在 PTX3，印迹显示受感染小牛肺中 PTX3 的表达显着增加。免疫金电子显微镜显示 PTX3 在肺泡巨噬细胞、内皮细胞和肺血管内巨噬细胞 (PIM) 的细胞核、细胞质和囊泡细胞器中。外周血中性粒细胞中 PTX3 的免疫组织化学染色显示，用脂多糖 (LPS) 刺激的中性粒细胞染色模式发生改变。然而，与对照相比，蛋白质印迹在 LPS 处理的中性粒细胞中 PTX3 的量没有显着变化。