Institute of Virology and Immunology, Bern & Mittelhäusern, Switzerland.
Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Eur J Immunol. 2020 Nov;50(11):1691-1711. doi: 10.1002/eji.202048643. Epub 2020 Jul 28.
Dendritic cells (DC) and monocytes are vital for the initiation of innate and adaptive immune responses. Recently, we identified bona fide DC subsets in blood of cattle, revealing subset- and species-specific transcription of toll-like receptors (TLR). In the present study, we analyzed phenotypic and transcriptional responses of bovine DC subsets and monocytes to in vitro stimulation with four to six different TLR ligands. Bovine DC subsets, especially plasmacytoid DC (pDC), showed a clear increase of CCR7, CD25, CD40, CD80, CD86, and MHC-II expression both on mRNA and protein level. Flow cytometric detection of p38 MAPK phosphorylation 15 min after stimulation confirmed activation of DC subsets and monocytes in accordance with TLR gene expression. Whole-transcriptome sequencing of sorted and TLR-stimulated subsets revealed potential ligand- and subset-specific regulation of genes associated with inflammation, T-cell co-stimulation, migration, metabolic reprogramming, and antiviral activity. Gardiquimod was found to evoke strong responses both in DC subsets and monocytes, while Poly(I:C) and CpG preferentially triggered responses in cDC1 and pDC, respectively. This in-depth analysis of ligand responsiveness is essential for the rational design of vaccine adjuvants in cattle, and provides a solid basis for comparative studies on DC and monocyte biology across species.
树突状细胞（DC）和单核细胞对于先天和适应性免疫反应的启动至关重要。最近，我们在牛的血液中鉴定了真正的 DC 亚群，揭示了 TLR 的亚群和物种特异性转录。在本研究中，我们分析了牛 DC 亚群和单核细胞对四种至六种不同 TLR 配体的体外刺激的表型和转录反应。牛 DC 亚群，尤其是浆细胞样 DC（pDC），在 mRNA 和蛋白水平上均表现出 CCR7、CD25、CD40、CD80、CD86 和 MHC-II 表达的明显增加。刺激后 15 分钟通过流式细胞术检测 p38 MAPK 磷酸化证实了 DC 亚群和单核细胞的激活，与 TLR 基因表达一致。对分选和 TLR 刺激的亚群进行的全转录组测序揭示了与炎症、T 细胞共刺激、迁移、代谢重编程和抗病毒活性相关的基因的潜在配体和亚群特异性调节。发现格地喹酮在 DC 亚群和单核细胞中均能引起强烈反应，而 Poly(I:C) 和 CpG 分别优先触发 cDC1 和 pDC 的反应。这种对配体反应性的深入分析对于牛疫苗佐剂的合理设计至关重要，并为跨物种的 DC 和单核细胞生物学比较研究提供了坚实的基础。
