title: PD-L1 expression is increased in monocyte derived dendritic cells in response to porcine circovirus type 2 and porcine reproductive and respiratory syndrome virus infections.
abstract: Host immune system suppression is thought to be crucial in the development of porcine circovirus associated diseases (PCVAD). Many immune suppressive mechanisms have been studied in cases of PCVAD, however, the role of programmed death ligand-1 (PD-L1) during porcine circovirus type 2 (PCV2) infection and PCVAD development has yet to be determined. PD-L1 has become an important research target because of its ability to interfere with effective T-cell activity and proliferation during the course of an immune response. In this study, porcine monocyte derived dendritic cells (MoDC) were infected with different combinations of PCV2 and porcine reproductive and respiratory syndrome virus (PRRSV) and evaluated for expression levels of PD-L1, as well as the expression levels of swine major histocompatibility complexes 1 and 2 (SLA-1 and SLA-2) as a measure of MoDC stimulatory capacity. PD-L1 expression levels were also tested in MoDCs after treatment with interferon alpha (IFN-α) and beta (IFN-β). The results showed that the expression levels of PD-L1 were increased in PCV2-infected MoDCs, as well as in PCV2 and PRRSV co-infected MoDCs. The MoDCs infected with PRRSV only also showed a strain-dependent increase in PD-L1 expression. Both IFN-α and IFN-β treatment also increased the expression levels of PD-L1 in MoDCs. SLA-1 and 2 expression levels were increased by PCV2 infection, and altered in the PRRSV, and PCV2+PRRSV co-infected MoDCs in a strain-dependent manner. These results indicate a potential immuno-suppressive role for dendritic cells during PCV2 infection and the development of PCVAD and will be helpful in more fully elucidating the underlying mechanisms leading to clinical PCVAD.
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States.
authors.forename: O
authors.initials: O
authors.lastname: Richmond
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States. Electronic address: tcecere@vt.edu.
authors.forename: T E
authors.initials: TE
authors.lastname: Cecere
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States.
authors.forename: E
authors.initials: E
authors.lastname: Erdogan
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States.
authors.forename: X J
authors.initials: XJ
authors.lastname: Meng
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States.
authors.forename: P
authors.initials: P
authors.lastname: Piñeyro
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States.
authors.forename: S
authors.initials: S
authors.lastname: Subramaniam
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States.
authors.forename: S M
authors.initials: SM
authors.lastname: Todd
authors.affiliation: Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, United States.
authors.forename: T
authors.initials: T
authors.lastname: LeRoith
mesh_terms: D000818:Animals; D060890:B7-H1 Antigen / Q000235:genetics / Q000378:metabolism*; D018173:Circoviridae Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary*; D017925:Circovirus; D003713:Dendritic Cells / Q000276:immunology; D007108:Immune Tolerance; D066298:In Vitro Techniques; D007370:Interferon Type I / Q000008:administration & dosage; D008285:Major Histocompatibility Complex; D009000:Monocytes / Q000276:immunology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000235:genetics / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034421:Sus scrofa; D013552:Swine; D013553:Swine Diseases / Q000235:genetics / Q000276:immunology*; D015854:Up-Regulation
chemical_list: D060890:B7-H1 Antigen; D007370:Interferon Type I; D012333:RNA, Messenger
keywords: Co-infection; Monocyte derived dendritic cells (MoDC); Porcine circovirus associated disease (PCVAD); Porcine circovirus type 2 (PCV2); Porcine reproductive and respiratory syndrome virus (PRRSV); Programmed death ligand-1 (PD-L1)