Nefefe T, Liebenberg J, van Kleef M, Steyn H C, Pretorius A
Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort, 0110, South Africa; Department of Veterinary Tropical Diseases, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort, 0110, South Africa.
Mol Immunol. 2017 Nov;91:238-248. doi: 10.1016/j.molimm.2017.09.018. Epub 2017 Oct 5.
Heartwater is a tick-borne non-infectious fatal disease of wild and domestic ruminants caused by the bacterium Ehrlichia ruminantium, transmitted by Amblyomma ticks. Although there is evidence that interferon-gamma (IFN-γ) controls E. ruminantium growth and that cellular immune responses could be protective, an effective recombinant vaccine for this disease is lacking. An overall analysis of which immune pathways are up- or down-regulated in sheep peripheral blood mononuclear cells is expected to lead to a better understanding of the global immune response of sheep to E. ruminantium infection. Therefore, a systems biology oriented approach following the infection with E. ruminantium was investigated from peripheral blood mononuclear cells to aid recombinant vaccine development. In this study, heartwater naïve sheep were infected and challenged by allowing E. ruminantium infected ticks to feed on them. After primary infection, all the animals were treated with antibiotic during the resulting febrile response. Blood was collected daily for E. ruminantium detection by qPCR (pCS20 assay). The pCS20 assay only detected the pathogen in the blood one day prior to and during the febrile stage of infection confirming infection of the sheep. IFN-γ real-time PCR indicated that this cytokine was expressed at specific time points: post infection, during the febrile stage of the disease and after challenge. These were used as a guide to select samples for transcriptome sequencing. This paper focuses on transcripts that are associated with innate activating pathways that were identified to be up- and down-regulated after primary infection and the subsequent challenge. These included the CD14 monocyte marker, toll-like receptor (TLR), nod-like receptor, chemokine, cytosolic and cytokine-cytokine interaction receptor pathways. In particular, TLR4, TLR9 and CD14 were activated together with DNA detection pathways, suggesting that vaccine formulations may be improved if CpG motifs and lipopolysaccharides are included. This data indicates that innate immune activation, perhaps by using adjuvants, should be an important component for consideration during future heartwater recombinant vaccine development.
心水病是一种由反刍动物埃立克体引起的、通过钝缘蜱传播的蜱媒性野生和家养反刍动物非传染性致命疾病。尽管有证据表明干扰素-γ（IFN-γ）可控制反刍动物埃立克体的生长，且细胞免疫反应可能具有保护作用，但目前仍缺乏针对该病的有效重组疫苗。对绵羊外周血单核细胞中哪些免疫途径上调或下调进行全面分析，有望更好地了解绵羊对反刍动物埃立克体感染的整体免疫反应。因此，研究了一种从外周血单核细胞入手、以系统生物学为导向的反刍动物埃立克体感染后方法，以协助重组疫苗的研发。在本研究中，让未感染心水病的绵羊被感染反刍动物埃立克体的蜱叮咬，从而使其感染并受到攻击。初次感染后，所有动物在发热反应期间接受抗生素治疗。每天采集血液，通过qPCR（pCS20检测法）检测反刍动物埃立克体。pCS20检测法仅在感染发热阶段前一天和发热阶段期间在血液中检测到病原体，证实绵羊已被感染。IFN-γ实时PCR表明，这种细胞因子在特定时间点表达：感染后、疾病发热阶段以及攻击后。这些被用作选择样本进行转录组测序的指导。本文重点关注与先天激活途径相关的转录本，这些转录本在初次感染和随后的攻击后被确定为上调和下调。这些途径包括CD14单核细胞标志物、Toll样受体（TLR）、NOD样受体、趋化因子、胞质和细胞因子-细胞因子相互作用受体途径。特别是，TLR4、TLR9和CD14与DNA检测途径一起被激活，这表明如果包含CpG基序和脂多糖，疫苗配方可能会得到改进。该数据表明，也许通过使用佐剂激活先天免疫，应成为未来心水病重组疫苗研发过程中需要考虑的重要组成部分。
