Immuno-modulating properties of Tulathromycin in porcine monocyte-derived macrophages infected with porcine reproductive and respiratory syndrome virus

PLoS One. 2019 Aug 23;14(8):e0221560. doi: 10.1371/journal.pone.0221560. eCollection 2019.

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-stranded RNA virus that grows in macrophages and causes acute pneumonia in pigs. PRRSV causes devastating losses to the porcine industry. However, due to its high antigenic variability and poorly understood immunopathogenesis, there is currently no effective vaccine or treatment to control PRRSV infection. The common occurrence of PRRSV infection with bacterial infections as well as its inflammatory-driven pathobiology raises the question of the value of antibiotics with immunomodulating properties for the treatment of the disease it causes. The macrolide antibiotic Tulathromycin (TUL) has been found to exhibit potent anti-inflammatory and immunomodulating properties in cattle and pigs. The aim of this study was to characterize the anti-viral and immunomodulating properties of TUL in PRRSV-infected porcine macrophages. Our findings indicate that blood monocyte-derived macrophages are readily infected by PRRSV and can be used as an effective cellular model to study PRRSV pathogenesis. TUL did not change intracellular or extracellular viral titers, not did it alter viral receptors (CD163 and CD169) expression on porcine macrophages. In contrast, TUL exhibited potent immunomodulating properties, which therefore occurred in the absence of any direct antiviral effects against PRRSV. TUL had an additive effect with PRRSV on the induction of macrophage apoptosis, and inhibited virus-induced necrosis. TUL significantly attenuated PRRSV-induced macrophage pro-inflammatory signaling (CXCL-8 and mitochondrial ROS production) and prevented PRRSV inhibition of non-opsonized and opsonized phagocytic function. Together, these data demonstrate that TUL inhibits PRRSV-induced inflammatory responses in porcine macrophages and protects against the phagocytic impairment caused by the virus. Research in live pigs is warranted to assess the potential clinical benefits of this antibiotic in the context of virally induced inflammation and tissue injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • Apoptosis / drug effects
  • Cell Differentiation / drug effects
  • Cell Line
  • Cell Shape / drug effects
  • Disaccharides / pharmacology*
  • Disaccharides / therapeutic use
  • Female
  • Heterocyclic Compounds / pharmacology*
  • Heterocyclic Compounds / therapeutic use
  • Immunologic Factors / pharmacology*
  • Immunologic Factors / therapeutic use
  • Interleukin-10 / metabolism
  • Interleukin-8 / metabolism
  • Intracellular Space / metabolism
  • Macrophages / drug effects
  • Macrophages / virology*
  • Male
  • Mice
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Necrosis
  • Opsonin Proteins / metabolism
  • Phagocytosis / drug effects
  • Porcine Reproductive and Respiratory Syndrome / drug therapy
  • Porcine Reproductive and Respiratory Syndrome / pathology*
  • Porcine respiratory and reproductive syndrome virus / drug effects
  • Porcine respiratory and reproductive syndrome virus / physiology*
  • Reactive Oxygen Species / metabolism
  • Receptors, Cell Surface
  • Receptors, Virus / metabolism
  • Sialic Acid Binding Ig-like Lectin 1 / metabolism
  • Swine
  • Virus Replication / drug effects

Substances

  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD163 antigen
  • Disaccharides
  • Heterocyclic Compounds
  • Immunologic Factors
  • Interleukin-8
  • Opsonin Proteins
  • Reactive Oxygen Species
  • Receptors, Cell Surface
  • Receptors, Virus
  • Sialic Acid Binding Ig-like Lectin 1
  • Interleukin-10
  • tulathromycin

Grants and funding

This work was supported by the Margaret Gunn Endowment For Animal Health Research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.