title: Replacement of Porcine CD163 Scavenger Receptor Cysteine-Rich Domain 5 with a CD163-Like Homolog Confers Resistance of Pigs to Genotype 1 but Not Genotype 2 Porcine Reproductive and Respiratory Syndrome Virus.
abstract: CD163 knockout (KO) pigs are resistant to infection with genotype 2 (type 2) porcine reproductive and respiratory syndrome virus (PRRSV). Furthermore, the substitution of CD163 scavenger receptor cysteine-rich (SRCR) domain 5 with a homolog of human CD163-like (hCD163L1) SRCR 8 domain confers resistance of transfected HEK cells to type 1 PRRSV. As a means to understand the role of domain 5 in PRRSV infection with both type 1 and type 2 viruses, pigs were genetically modified (GM) to possess one of the following genotypes: complete knockout (KO) of CD163, deletions within SRCR domain 5, or replacement (domain swap) of SRCR domain 5 with a synthesized exon encoding a homolog of hCD163L1 SRCR domain 8. Immunophenotyping of porcine alveolar macrophages (PAMs) showed that pigs with the KO or SRCR domain 5 deletion did not express CD163. When placed in culture, PAMs from pigs with the CD163 KO phenotype were completely resistant to a panel consisting of six type 1 and nine type 2 isolates. PAMs from pigs that possessed the hCD163L1 domain 8 homolog expressed CD163 and supported the replication of all type 2 isolates, but no type 1 viruses. Infection of CD163-modified pigs with representative type 1 and type 2 viruses confirmed the in vitro results. The results confirm that CD163 is the likely receptor for all PRRS viruses. Even though type 1 and type 2 viruses are considered phenotypically similar at several levels, there is a distinct difference between the viral genotypes in the recognition of CD163.
  
  
  OBJECTIVE
  Genetic modification of the CD163 gene creates the opportunity to develop production animals that are resistant to PRRS, the costliest viral disease to ever face the swine industry. The results create further opportunities to develop refinements in the modification of CD163 with the goal of making pigs refractory to infection while retaining important CD163 functions.
authors.affiliation: Division of Animal Science, College of Food Agriculture and Natural Resources, University of Missouri, Columbia, Missouri, USA.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Wells
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Bardot
authors.affiliation: Division of Animal Science, College of Food Agriculture and Natural Resources, University of Missouri, Columbia, Missouri, USA.
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Whitworth
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Trible
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Genus, PLC, DeForest, Wisconsin, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Mileham
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Kerrigan
authors.affiliation: Division of Animal Science, College of Food Agriculture and Natural Resources, University of Missouri, Columbia, Missouri, USA.
authors.forename: Melissa S
authors.initials: MS
authors.lastname: Samuel
authors.affiliation: Division of Animal Science, College of Food Agriculture and Natural Resources, University of Missouri, Columbia, Missouri, USA.
authors.forename: Randall S
authors.initials: RS
authors.lastname: Prather
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA browland@vet.k-state.edu.
authors.forename: Raymond R R
authors.initials: RRR
authors.lastname: Rowland
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics*; D023061:Gene Order; D056426:Genetic Loci; D020022:Genetic Predisposition to Disease; D005838:Genotype; D054884:Host-Pathogen Interactions / Q000235:genetics; D016676:Macrophages, Alveolar / Q000276:immunology / Q000378:metabolism / Q000821:virology; D009154:Mutation; D010641:Phenotype; D019318:Porcine Reproductive and Respiratory Syndrome / Q000235:genetics* / Q000378:metabolism / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000502:physiology*; D054730:Protein Interaction Domains and Motifs / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013552:Swine; D019562:Viral Load; D000098902:CD163 Antigen
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000098902:CD163 Antigen; D011956:Receptors, Cell Surface
keywords: CD163; genetic modification; porcine reproductive and respiratory syndrome virus