Sialoadhesin is not required for infection of pigs with PRRSV-1

Sialoadhesin (Sn/SIGLEC1/CD169) is a macrophage surface protein belonging to a family of sialic acid binding immunoglobulin-like lectins. Classic models of PRRSV infection show that the first step in the infection of a macrophage is the binding of CD169 with the virion surface protein GP5. Previously, our lab discovered that CD169 knockout (KO) pigs support productive infection with PRRSV-2. Since PRRSV-1 and PRRSV-2 share only about 70% nucleotide identity and possess different requirements for infection of macrophages, we conducted a second study to determine if CD169 KO pigs could be infected with a PRRSV-1 isolate. KO pigs (n=8) and wild type pigs (WT, n=9) were infected with EU PRRSV-1 strain, SD01-08, and maintained for 28 days. Both genotypes were maintained in the same room and personnel were blind as to the genotype of individual pigs. Serum and tissues were collected and evaluated for infection using a commercial RT-qPCR kit. Antibody was measured using a commercial ELISA kit from IDEXX. Lung, tonsil, and submandibular lymph node tissue were extracted on day 28 for evaluation of viral RNA. Results from Serum and ELISA assays showed that all pigs in the wild-type (WT) and KO pigs supported PRRSV infection. Significant differences were observed in viral nucleic acid between WT and KO pigs at 21 (p = 0.002) and 28 (p = 0.023) days after infection. ELISA antibody analysis revealed statistically significant differences at 28 days post infection (p = 0 .021). Area under the curve analysis of viremia showed that the CD169 KO pigs supported higher virus loads. Analysis of tissues revealed no statistical differences between KO and WT pigs in tonsil and lymph node, while virus nucleic acid template copies were significantly higher in lung tissue from KO pigs. These results confirm that the presence of CD169 is not biologically relevant for PRRSV infection. Increased levels of viremia in KO pigs may be related to immune modulation by CD169, given the receptor is responsible for cell-to-cell interactions during antigen processing and presentation.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

VMS - Pathobiology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Salgado, Brianna Crystine

Contributors dc:contributor

• Rowland, Raymond R
• Love, James F
• Fang, Ying

• Prrsv-1 Sialoadhesin Cd169 Sn

Statement dc:rights

• Copyright 2024 Brianna Salgado

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/124364

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F124364