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Identification Of The Laminin Receptor As A Cellular Attachment Receptor For Classical Swine Fever Virus

Posted on:2016-06-01Degree:DoctorType:Dissertation
Country:ChinaCandidate:J N ChenFull Text:PDF
GTID:1223330461989461Subject:Prevention of Veterinary Medicine
Abstract/Summary:PDF Full Text Request
Viruses, with incomplete system of metabolic system, rely on the host cell to complete the viral life cycle. Viral entry starts with specific interactions of virion with cellular surface components, i.e. cellular receptors. The interactions between viral attachment proteins and cellular receptors are thought to determine the tissue tropism and host range for viruses. More importantly, antiviral strategies can be designed to prevent virus invasion by blocking the virus-receptor interaction. Thus, the study of cellular receptors is of great importance.Classical swine fever virus(CSFV) is the causative agent of classical swine fever(CSF), a highly contagious, economically important viral disease in many countries. In recent years, CSFV-host interactions have been defined more clearly with better understanding of the mechanisms. But there is still little knowledge about CSFV entry. To date, only one cellular receptor, heparan sulfate(HS), has been identified as being involved in CSFV attachment. HS is also present on the surface of various cells that are nonpermissive to CSFV. Hence, there must be another receptor(s) that has been unidentified to date.In this study, we used a set of small interfering RNAs(si RNAs) against a number of porcine cell membrane protein genes to screen cellular proteins involved in CSFV infection. This approach resulted in the identification of several proteins, and of these, the laminin receptor(Lam R) has been demonstrated to be a cellular receptor for several viruses. Confocal analysis showed that Lam R is colocalized with CSFV virions on the membrane, and a coimmunoprecipitation assay indicated that Lam R interacts with the CSFV Erns protein. In inhibition assays, anti-Lam R antibodies, soluble laminin or Lam R protein significantly inhibited CSFV infection in a dose-dependent manner. Transduction of PK-15 cells with a recombinant lentivirus expressing Lam R yielded higher viral titers. Moreover, an attachment assay demonstrated that Lam R functions during virus attachment. We also demonstrated that Lam R acts as an alternative attachment receptor, especially in SK6 cells. But in our study, we showed that the expression of Lam R did not correlate with the CSFV tropism to different tissues. The knockdown of Lam R did not inhibit BVDV replication. This suggested Lam R may not be the cellular receptor for BVDV.Overall, we used si RNAs against a number of porcine cell membrane protein genes to screen cellular factors involved in the infection and identified Lam R as a cellular attachment receptor for CSFV.
Keywords/Search Tags:Classical swine fever virus, Cellular receptor, Laminin receptor, Heparan sulfate
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