Exploring PTX3 expression in Sus scrofa cardiac tissue using RNA sequencing

Pentraxins in invertebrates and vertebrates: From structure, function and evolution to clinical applications

The immune system is divided into two broad categories, consisting of innate and adaptive immunity. As recognition and effector factors of innate immunity and regulators of adaptive immune responses, lectins are considered to be important defense chemicals against microbial pathogens, cell trafficking, immune regulation, and prevention of autoimmunity. Pentraxins, important members of animal lectins, play a significant role in protecting the body from pathogen infection and regulating inflammatory reactions. They can recognize and bind to a variety of ligands, including carbohydrates, lipids, proteins, nucleic acids and their complexes, and protect the host from pathogen invasion by activating the complement cascade and Fcγ receptor pathways. Based on the primary structure of the subunit, pentraxins are divided into short and long pentraxins. The short pentraxins are comprised of C-reactive protein (CRP) and serum amyloid P (SAP), and the most important member of the long pentraxins is pentraxin 3 (PTX3). The CRP and SAP exist in both vertebrates and invertebrates, while the PTX3 may be present only in vertebrates. The major ligands and functions of CRP, SAP and PTX3 and three activation pathways involved in the complement system are summarized in this review. Their different characteristics in various animals including humans, and their evolutionary trees are analyzed. The clinical applications of CRP, SAP and PTX3 in human are reviewed. Some questions that remain to be understood are also highlighted.

Pentraxin 3 expression in lungs and neutrophils of calves

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.

Immune characterization of long pentraxin 3 in pigs infected with influenza virus

Long pentraxin 3 (PTX3) is a conserved pattern-recognition secreted protein and a host-defence-related component of the humoral innate immune system. The aim of the present study was to characterize swine PTX3 (SwPTX3) protein expression in influenza virus infected pigs. First, we performed in silico studies to evaluate the cross-reactivity of PTX3 human antibodies against SwPTX3. Secondly, we used in vitro analysis to detect SwPTX3 presence in swine bone marrow dendritic cells (SwBMDC) upon stimulation with different agents by Western blot and immunofluorescence. Finally, the levels of SwPTX3 were assessed in experimental infection of pigs with different strains of influenza virus. This is a novel study where the expression of SwPTX3 was evaluated in the context of a pathogen infection. The initial characterization of SwPTX3 in influenza virus infected pigs contributes to understand the role of PTX proteins in the immune response.