Human neutrophils activated by TLR8 agonists, with or without IFNγ, synthesize and release EBI3, but not IL-12, IL-27, IL-35, or IL-39. Issue 5 (1st June 2020)

• Record Type: Journal Article
• Authors: Cassatella, Marco A; Gardiman, Elisa; Arruda-Silva, Fabio; Bianchetto-Aguilera, Francisco; Gasperini, Sara; Bugatti, Mattia; Vermi, William; Larousserie, Frederique; Devergne, Odile; Tamassia, Nicola
• Is Part Of: Journal of leukocyte biology. Volume 108:Issue 5(2020)
• Page Start: 1515
• Page End: 1526
• Publication Date: 2020-06-01
• Subjects: EBI3 -- IL-12 -- IL-27 -- IL-35 -- Neutrophils -- TLR8 -- TNFα; Leucocytes -- Periodicals; Reticulo-endothelial system -- Periodicals; 571.96
• DOI: 10.1002/JLB.3MA0520-054R
• Languages: English
• ISSNs: 0741-5400

Abstract

Abstract: The IL-12 family of cytokines plays crucial functions in innate and adaptive immunity. These cytokines include heterodimers sharing distinct α (IL-12A, IL-23A, and IL-27A) with two β (IL-12B and Epstein-Barr virus induced gene 3 [EBI3]) chains, respectively, IL-12 (IL-12B plus IL-12A) and IL-23 (IL-12B plus IL-23A) sharing IL-12B, IL-27 (EBI3 plus IL-27A), IL-35 (EBI3 plus IL-12A), and IL-39 (EBI3 plus IL-23A) sharing EBI3. In this context, we have recently reported that highly pure neutrophils incubated with TLR8 agonists produce functional IL-23. Previously, we showed that neutrophils incubated with LPS plus IFNγ for 20 h produce IL-12. Herein, we investigated whether highly pure, TLR8-activated, neutrophils produce EBI3, and in turn IL-27, IL-35, and IL-39, the IL-12 members containing it. We report that neutrophils incubated with TLR8 ligands, TNFα and, to a lesser extent, LPS, produce and release remarkable amounts of EBI3, but not IL-27A, consequently excluding the possibility for an IL-27 production. We also report a series of unsuccessful experiments performed to investigate whether neutrophil-derived EBI3 associates with IL-23A to form IL-39. Furthermore, we show that neutrophils incubated with IFNγ in combination with either TLR8 or TLR4 ligands express/produce neither IL-12, nor IL-35, due to the inability of IFNγ, contrary to previous findings, to activate IL12A transcription. Even IL-27 was undetectable in supernatants harvested from IFNγ plus R848-treated neutrophils, although they were found to accumulate IL27A transcripts. Finally, by immunohistochemistry experiments, EBI3-positive neutrophils were found in discrete pathologies only, including diverticulitis, cholecystitis, Gorham disease, and Bartonella Henselae infection, implying a specific role of neutrophil-derived EBI3 in vivo. Graphical Abstract: Human neutrophils incubated with TLR8 agonists, in the absence or the presence of IFNγ, produce and release EBI3 but not IL-12, IL-27 or IL-35