Isolation and characterization of a new population of nasal surface macrophages and their susceptibility to PRRSV-1 subtype 1 (LV) and subtype 3 (Lena)

Abstract

Sialoadhesin (Sn) and CD163 have been recognized as two important mediators for porcine reproductive and respiratory syndrome virus (PRRSV) in host macrophages. Recently, it has been demonstrated that the highly virulent Lena strain has a wider macrophage tropism than the low virulent LV strain in the nasal mucosa. Not only CD163 + Sn + macrophages are infected by Lena but also CD163 + Sn − macrophages. This suggests that an alternative receptor exists for binding and internalization of PRRSV Lena in the CD163 + Sn − macrophages. Further investigation to find the new entry receptor was hampered by the difficulty of isolating these macrophages from the nasal mucosa. In the present study, a new population of CD163 + Sn − cells has been identified that is specifically localized in the nasal lamina propria and can be isolated by an intranasal digestion approach. Isolated nasal cells were characterized using specific cell markers and their susceptibility to two different PRRSV-1 strains (LV and Lena) was tested. Upon digestion, 3.2% (flow cytometry)-6.4% (confocal microscopy) of the nasal cells were identified as CD163 + and all (99.7%) of these CD163 + cells were Sn −. These CD163 + Sn − cells, designated as "nasal surface macrophages", showed a 4.9 times higher susceptibility to the Lena strain than to the LV strain. Furthermore, the Lena-inoculated cell cultures showed an upregulation of CD163. These results showed that our new cell isolation system is ideal for the further functional and phenotypical analysis of the new population of nasal surface macrophages and further research on the molecular pathogenesis of PRRSV in the nose.

Osteoinductive calcium phosphate with submicron topography as bone graft substitute for maxillary sinus floor augmentation: A translational study

“…However, the Schneiderian membrane has been shown to be osteogenic, since it harbors a niche of mesenchymal osteoprogenitor cells (Berbéri et al, 2017;Graziano et al, 2012;Gruber et al, 2004;Li et al, 2015). Furthermore, mucosal epithelia such as the Schneiderian membrane are known to contain high numbers of immune cells, including macrophages, because they form a primary defense against invading pathogens (Oh et al, 2020;Russell et al, 2015). In light of earlier results that have Interestingly, the mean area percentages of bone in available space for BCP N and ABG in the sheep study were comparable to the values obtained in the clinical study, while mean area percentages of residual graft material and combined bone and graft material were also similar for BCP N between the two studies.…”

“…However, the Schneiderian membrane has been shown to be osteogenic, since it harbors a niche of mesenchymal osteoprogenitor cells (Berbéri et al, 2017; Graziano et al, 2012; Gruber et al, 2004; Li et al, 2015). Furthermore, mucosal epithelia such as the Schneiderian membrane are known to contain high numbers of immune cells, including macrophages, because they form a primary defense against invading pathogens (Oh et al, 2020; Russell et al, 2015). In light of earlier results that have suggested a role for macrophages in bone induction, it is possible that macrophages from the Schneiderian may have migrated to the nearby implanted bone grafts, and subsequently polarized to the pro‐regenerative M2 phenotype.…”

The Ability of Porcine Reproductive and Respiratory Syndrome Virus Isolates to Induce Broadly Reactive Neutralizing Antibodies Correlates With In Vivo Protection

“…Besides, this isolate has been classified as an isolate of high virulence based on the severity of the clinical signs and lesions recorded in a study carried out in 3-week-old pigs in the respiratory model of the disease ( 44 ). Virulence might be a relevant characteristic because it has been demonstrated that PRRSV-1 isolates of higher virulence replicate more efficiently in the host ( 45 , 46 ) and in a wider range of cellular types ( 47 , 48 ), and it can be speculated that this better in vivo replication might help to overcome any previously existing immunity, either humoral or cellular.…”

Porcine Macrophage Markers and Populations: An Update

“…Nauwynck’s group characterized macrophage populations in nasal mucosa, as this represents a primary entry site for many pathogens, including PRRSV [ 254 , 255 ]. These authors identified two major populations: CD163 + CD169 − cells, located in the upper lamina propria and within the epithelium, and CD163 + CD169 + cells, predominantly found in the deeper area of lamina propria , close to the cartilage.…”