Data from: Adhesion forces and mechanics in mannose-mediated acanthamoeba interactions

The human pathogenic amoeba Acanthamoeba castellanii (A. castellanii) causes severe diseases, including acanthamoeba keratitis and encephalitis. Pathogenicity arises from the killing of target-cells by an extracellular killing mechanism, where the crucial first step is the formation of a close contact between A. castellanii and the target-cell. This process is mediated by the glycocalix of the target-cell and mannose has been identified as key mediator. The aim of the present study was to carry out a detailed biophysical investigation of mannose-mediated adhesion of A. castellanii using force spectroscopy on single trophozoites. In detail, we studied the interaction of a mannose-coated cantilever with an A. castellanii trophozoite, as mannose is the decisive part of the cellular glycocalix in mediating pathogenicity. We observed a clear increase of the force to initiate cantilever detachment from the trophozoite with increasing contact time. This increase is also associated with an increase in the work of detachment. Furthermore, we also analyzed single rupture events during the detachment process and found that single rupture processes are associated with membrane tether formation, suggesting that the cytoskeleton is not involved in mannose binding events during the first few seconds of contact. Our study provides an experimental and conceptual basis for measuring interactions between pathogens and target-cells at different levels of complexity and as a function of interaction time, thus leading to new insights into the biophysical mechanisms of parasite pathogenicity.

人致病性阿米巴卡氏棘阿米巴（Acanthamoeba castellanii，下称A. castellanii）可引发包括棘阿米巴角膜炎、脑炎在内的严重疾病。其致病机制依赖于通过胞外杀伤途径杀灭靶细胞，其中关键起始步骤为卡氏棘阿米巴与靶细胞形成紧密接触。该过程由靶细胞的糖萼（glycocalix）介导，而甘露糖已被证实为核心介导因子。本研究旨在借助单滋养体（trophozoite）力谱（force spectroscopy）技术，对卡氏棘阿米巴甘露糖介导的黏附过程开展细致的生物物理研究。具体而言，我们探究了包被甘露糖的悬臂（cantilever）与卡氏棘阿米巴滋养体之间的相互作用——鉴于甘露糖是细胞糖萼中介导致病效应的决定性组分。实验结果显示，随着接触时间延长，使悬臂从滋养体上脱离所需的临界力显著升高，且该力的提升同步伴随脱离功的增加。此外，我们还分析了脱离过程中的单次破裂事件，发现单次破裂过程与膜栓（membrane tether）的形成存在关联，这表明在接触初始数秒内，细胞骨架并未参与甘露糖结合事件。本研究为在不同复杂程度下、基于相互作用时长测量病原体与靶细胞间的相互作用提供了实验与概念基础，进而为解析寄生虫致病的生物物理机制提供了全新视角。