Not All Polyriboinosinic-polyribocytidylic Acids (Poly I:C) are Equivalent for Inducing Maturation of Dendritic Cells

Abstract

This study compares the behavior of 2 commercially available polyriboinosinic-polyribocytidylic acids (poly I:C1 and poly I:C2) and the structural analog poly I:C12U in regard to dendritic cell (DC) maturation. When the Toll-like receptor 3 (TLR3) agonists are tested in combination with interferon-alpha, tumor necrosis factor-alpha, interleukin (IL)-1beta, and interferon-gamma (the so-called alpha-type-1 DC), the 3 different cocktails generate phenotypically mature DCs, but with different functional properties. Higher migratory capacity is observed with poly I:C1, the only poly I:C allowing spontaneous release of IL-12p70 by DCs. However, upon CD40 triggering, cocktails containing poly I:C2 or poly I:C12U allow a far higher production of IL-12p70 compared with those containing poly I:C1. Using a TLR signaling pathway reverse transcription profiler polymerase chain reaction to analyze changes in gene expression after treatment of DCs with the agonists alone, we show that 39% of the 84 tested genes are differentially regulated between the 3 conditions. Poly I:C12U induces far fewer regulated genes than the 2 other poly I:Cs. These different behaviors could be due to alternative ways of sensing double-stranded RNA, which do not rely solely on TLR3 but also on other types of receptors, depending on the size of poly I:Cs. As the 2 poly I:Cs tested here have very different molecular weights, this could partly explain the observed differences. In conclusion, neither the poly I:Cs nor their structural analog poly I:C12U have an equivalent behavior. This should be taken into an account not only when they are used in cocktails for DC maturation but also when analyzing signaling pathways with synthetic double-stranded RNA analogs.

Release of IL-12 by dendritic cells activated by TLR ligation is dependent on MyD88 signaling, whereas TRIF signaling is indispensable for TLR synergy

“…Moreover, these results indicate that MyD88-dependent signaling is central for release of IL-12, whereas synergy can be provided by a range of other quite different stimuli, such as muramyldipeptide, IFN-␥, ␣CD40, or signaling via TRIF. In this regard, we cannot confirm reports describing robust IL-12 production by DC merely stimulated with Poly (I:C) [30]. Indeed, experiments with MyD88 Ϫ/Ϫ DC proved that Poly (I:C) provided by some manufacturers can contain substantial endotoxin contaminations (data not shown).…”

Differential Responses of Normal Human Melanocytes to Intra- and Extracellular dsRNA

“…It is noticeable that the dsRNAs used in two studies were purchased from different providers. It is suggested previously that poly(I:C) with different lengths might display different effects (Avril et al, 2009;McNally et al, 2012). This may explain the discrepancy of outcomes from two studies.…”

Stimulation of the RIG-I/MAVS Pathway by Polyinosinic:Polycytidylic Acid Upregulates IFN-β in Airway Epithelial Cells with Minimal Costimulation of IL-8

“…Notably, several commercial formulations of poly(I:C) exist with potentially different effects on immune cells (56,57). The availability of various formulations of poly(I:C) may be advantageous, because its molecular size and chemical modifications play an important fine-tuning role in stimulating innate cell responses and may allow for a greater versatility in different pathologic conditions.…”