The anti-tuberculosis vaccine Bacillus Calmette-Guérin (BCG) is able to boost innate immune responses through a process called 'trained immunity'. It is hypothesized that BCG-induced trained immunity contributes to protection against Mycobacterium tuberculosis infection. Since alveolar macrophages are the first cell type to encounter M. tuberculosis upon infection, we aimed to investigate the immunomodulatory effects of BCG vaccination on alveolar macrophages. Searching for a less-invasive method than bronchoalveolar lavage, we optimized the isolation of alveolar macrophages from induced sputum of healthy volunteers. Viable alveolar macrophages could be successfully isolated from induced sputum and showed signs of activation already upon retrieval. Further flow cytometric analyses revealed that at baseline, higher expression levels of activation markers were observed on the alveolar macrophages of smokers compared to non-smokers. In addition, BCG vaccination resulted in decreased expression of the activation markers CD11b and HLA-DR on alveolar macrophages. Future studies should evaluate the functional consequences of this reduced activation of alveolar macrophages after BCG vaccination.

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卡介苗对健康志愿者诱导痰中肺泡巨噬细胞的影响

抗结核疫苗卡介苗 (BCG) 能够通过称为“训练免疫”的过程增强先天免疫反应。据推测，卡介苗诱导的受过训练的免疫有助于防止结核分枝杆菌感染。由于肺泡巨噬细胞是第一种在感染时遇到结核分枝杆菌的细胞类型，我们旨在研究卡介苗疫苗接种对肺泡巨噬细胞的免疫调节作用。为了寻找比支气管肺泡灌洗侵入性更小的方法，我们优化了从健康志愿者的诱导痰中分离肺泡巨噬细胞。活的肺泡巨噬细胞可以成功地从诱导痰中分离出来，并且在检索时已经显示出激活的迹象。进一步的流式细胞仪分析显示，在基线时，与非吸烟者相比，在吸烟者的肺泡巨噬细胞上观察到更高的活化标志物表达水平。此外，卡介苗疫苗接种导致肺泡巨噬细胞上激活标志物 CD11b 和 HLA-DR 的表达降低。未来的研究应该评估卡介苗接种后肺泡巨噬细胞活化减少的功能后果。