Bekkering Siroon, Blok Bastiaan A, Joosten Leo A B, Riksen Niels P, van Crevel Reinout, Netea Mihai G
Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen, Denmark.
Clin Vaccine Immunol. 2016 Dec 5;23(12):926-933. doi: 10.1128/CVI.00349-16. Print 2016 Dec.
Innate immune memory, or trained immunity, has recently been described to be an important property of cells of the innate immune system. Due to the increased interest in this important new field of immunological investigation, we sought to determine the optimal conditions for an in vitro experimental protocol of monocyte training using three of the most commonly used training stimuli from the literature: β-glucan, the bacillus Calmette-Guérin (BCG) vaccine, and oxidized low-density lipoprotein (oxLDL). We investigated and optimized a protocol of monocyte trained immunity induced by an initial training period with β-glucan, BCG, or oxLDL, followed by washing and resting of the cells and, thereafter, restimulation with secondary bacterial stimuli. The training and resting time intervals were varied to identify the optimal setting for the long-term induction of trained immunity. Trained immunity was assessed in terms of the secondary cytokine response, the production of reactive oxygen species, cell morphology, and induction of glycolysis. Monocytes primed with β-glucan, BCG, and oxLDL showed increased pro- and anti-inflammatory cytokine responses upon restimulation with nonrelated stimuli. Also, all three stimuli induced a switch to glycolysis (the Warburg effect). These effects were most pronounced when the training interval was 24 h and the resting time interval was 6 days. Training with BCG and oxLDL also led to the increased production of reactive oxygen species, whereas training with β-glucan led to the decreased production of reactive oxygen species. We describe the optimal conditions for an in vitro experimental model with human primary monocytes for study of the induction of trained innate immunity by microbial and metabolic stimuli.
固有免疫记忆，即训练免疫，最近被描述为固有免疫系统细胞的一项重要特性。鉴于对这一重要的免疫研究新领域的兴趣与日俱增，我们试图确定一种体外实验方案的最佳条件，该方案使用文献中三种最常用的训练刺激物：β-葡聚糖、卡介苗（BCG）疫苗和氧化型低密度脂蛋白（oxLDL）来训练单核细胞。我们研究并优化了一种单核细胞训练免疫方案，该方案包括先用β-葡聚糖、BCG或oxLDL进行初始训练期，然后洗涤细胞并使其静置，之后用二次细菌刺激物进行再刺激。我们改变训练和静置的时间间隔，以确定长期诱导训练免疫的最佳设置。从二次细胞因子反应、活性氧的产生、细胞形态以及糖酵解的诱导等方面评估训练免疫。用β-葡聚糖、BCG和oxLDL预处理的单核细胞在用无关刺激物再刺激时，促炎和抗炎细胞因子反应均增强。此外，所有三种刺激物均诱导细胞向糖酵解转变（瓦伯格效应）。当训练间隔为24小时且静置时间间隔为6天时，这些效应最为明显。用BCG和oxLDL训练还导致活性氧的产生增加，而用β-葡聚糖训练则导致活性氧的产生减少。我们描述了一种用于研究微生物和代谢刺激诱导训练固有免疫的体外实验模型的最佳条件，该模型使用人原代单核细胞。
