title: Splenic CD163+macrophages as targets of porcine reproductive and respiratory virus: Role of Siglecs.
abstract: CD169 and CD163 have been involved in the process of PRRS virus attachment and infection in macrophages, although recent studies have challenged the requirement for CD169. In addition to CD169, macrophages express other siglecs, whose role in PRRS virus infection is so far unknown. Splenic CD163+macrophages express Siglec-3 and Siglec-5 but almost undetectable levels of CD169. Hence, we considered this cell population appropriate for analysing the role of these siglecs in the attachment and internalization of PRRS virus into macrophages. PRRS virus replicated efficiently in these macrophages, yielding even higher titres than in alveolar macrophages. Besides, a recombinant protein consisting in the ectodomain of porcine Siglec-3 fused to the Fc fragment of human IgG1 (Siglec3-Fc) was able to bind PRRS virus, while binding to Siglec-5-Fc was inconsistent. Antibodies to CD169 but not to Siglec-3 or Siglec-5 blocked the binding and infection of PRRS virus on alveolar macrophages. Unexpectedly, our antibody to CD169 also blocked the binding of PRRS virus to splenic CD163+macrophages, whereas antibodies to Siglec-3 or Siglec-5 had no effect. These results show that very low levels of CD169 expression are enough to support the attachment and internalization of PRRS virus into macrophages, whereas Siglec-3 and Siglec-5 do not seem to contribute to the virus entry in these cells.
authors.affiliation: Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Yuste
authors.affiliation: Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Fernández-Caballero
authors.affiliation: Dpto. Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid 28040, Madrid, Spain.
authors.forename: Cinta
authors.initials: C
authors.lastname: Prieto
authors.affiliation: Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Álvarez
authors.affiliation: Dpto. Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid 28040, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Martínez-Lobo
authors.affiliation: Dpto. Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid 28040, Madrid, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Simarro
authors.affiliation: Dpto. Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid 28040, Madrid, Spain.
authors.forename: José María
authors.initials: JM
authors.lastname: Castro
authors.affiliation: Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Alonso
authors.affiliation: Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Ezquerra
authors.affiliation: Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Domínguez
authors.affiliation: Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain. Electronic address: crevilla@inia.es.
authors.forename: Concepción
authors.initials: C
authors.lastname: Revilla
mesh_terms: D000818:Animals; D000906:Antibodies / Q000378:metabolism; D015703:Antigens, CD / Q000378:metabolism*; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism*; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism* / Q000821:virology*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000378:metabolism*; D011485:Protein Binding; D000072417:Protein Domains / Q000235:genetics; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D063265:Sialic Acid Binding Immunoglobulin-like Lectins / Q000235:genetics / Q000378:metabolism*; D013552:Swine; D053585:Virus Attachment; D053586:Virus Internalization; D014779:Virus Replication; D000098902:CD163 Antigen
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000098902:CD163 Antigen; D007141:Immunoglobulin Fc Fragments; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D063265:Sialic Acid Binding Immunoglobulin-like Lectins
keywords: Alveolar macrophages; CD163; CD169; PRRS virus; Siglecs; Splenic red pulp macrophages