J Vet Sci.  2023 May;24(3):e37. 10.4142/jvs.23007.

In vitro effects of monophosphoryl lipid A and Poly I:C combination on equine cells

• Lee DH
• Lee Eb
• Seo Jp
• Ko EJ

• KMID: 2542989
• DOI: http://doi.org/10.4142/jvs.23007

Abstract

Background
Toll-like receptor (TLR) agonists have been used as adjuvants to modulate immune responses in both animals and humans.
Objectives
The objective of this study was to evaluate the combined effects of the TLR 4 agonist monophosphoryl lipid A (MPL) and the TLR 3 agonist polyinosinic:polycytidylic acid (Poly I:C) on equine peripheral blood mononuclear cells (PBMCs), monocyte-derived dendritic cells (MoDCs), and bone marrow-derived mesenchymal stromal cells (BM-MSCs).
Methods
The PBMCs, MoDCs, and BM-MSCs collected from three mixed breed horses were treated with MPL, Poly I:C, and their combination. The mRNA expression of interferon gamma (IFN-γ), interleukin (IL)-1β, IL-4, IL-6, IL-8, IL-12p40, tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), and monocyte chemoattractant protein-1 (MCP-1) was determined using real-time polymerase chain reaction.
Results
The combination of MPL and Poly I:C significantly upregulated immunomodulatory responses in equine cells/ without cytotoxicity. The combination induced greater mRNA expression of pro-inflammatory cytokines IFN-γ and IL-6 than MPL or Poly I:C stimulation alone in PBMCs. In addition, the combination induced significantly higher mRNA expression of IL-1β, IL-6, and IL-12p40 in MoDCs, and IL-8, MCP-1, and VEGF in BM-MSCs compared to stimulation with a single TLR agonist.
Conclusions
The combination of MPL and Poly I:C can be used as a potential adjuvant candidate for vaccines to aid in preventing infectious diseases in horses.

Keyword

Toll-Like Receptors; peripheral blood mononuclear cell; dendritic cells; bone marrow stromal cell; immunomodulation