Influence of Different Bacterial Lipopolysaccharides on Porcine Circovirus Type 2 Replication in Porcine Alveolar Macrophage
Date Issued
2008
Date
2008
Author(s)
Liu, Juan-Ting
Abstract
It has now been demonstrated that porcine circovirus type 2（PCV2） is the causative agent of postweaning multisystemic wasting syndrome（PMWS ). Pigs with PMWS show variable degree of lymphoid depletion with histiocytic and multinucleated giant cell infiltration in the lymphoid organs. Several questions remain unknown including the primary target cells and the permissive cells for the replication of PCV2, as well as the pathogenesis of PMWS in PCV2 infection. In in vivo experiments, monocyte/macrophage lineage cells including porcine alveolar macrophage（PAM）are the major target cells of PCV2. However, there was only high incidence of intracytoplasmic PCV2 signal but lack of intranuclear signals as well as no evidence of PCV2 replication in those cells in vitro. This finding is contradictory to what was found in the tissues of field pigs with PMWS in which both intracytoplasmic and intranuclear PCV2 signals were easily detected in the monocyte/macrophage lineage cells. Concurrent infection and activation of immune system, therefore, have been suggested that may promote PCV2 replication in vivo. Lipopolysaccharide（LPS） is a structural component of the outer membrane of Gram negative bacteria and the composition diversity of LPS between different bacterial species and strains are also observed. It has been demonstrated that LPS of Escherichia coli would induce replication of PCV2 in PAM. In the present study, LPS from different bacterial species, including E. coli, Salmonella enterica, Pseudomonas aeruginosa and Klebsiella pneumoniae, were used as stimulator for PCV2 replication in PAMs and the change in antigen distribution were further evaluated. The results of immunofluorecent assay (IFA) revealed not only the higher virulent LPS of E. coli and Salmonella enterica, but also the LPS from the lower virulent bacterium of non-obligate swine pathogens such as Pseudomonas aeruginosa and Klebsiella pneumoniae could slightly induce the replication of PCV2 in the nucleus of PAM. The quantitative real-time PCR of the culture supernatant revealed no difference between various treatments. The titration of the culture supernatant revealed mild increase of PCV2 replication in all LPS tested. The results of this study indicate that LPS from different bacterium process varied capability in inducing PCV2 replication in PAM. Nevertheless the level of induction is very mild. The result may provide part of explanation regarding of pathogenesis of PMWS.
Subjects
PCV2
porcine circovirus type 2
PAM
porcine alveolar macrophage
LPS
lipopolysaccharide
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95629009-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):131aa05b14c4030ef1e5ddef0dfb0ec2