棘阿米巴是一種自由營生的阿米巴原蟲，可引起眼睛和中樞神經系統的嚴重感染，造成相關疾病如：棘阿米巴性角膜炎（AK）和慢性肉芽腫性阿米巴腦膜炎（GAE）。然而，棘阿米巴的致病機制目前仍有待闡明。根據我們的初步結果顯示當細胞與致病性棘阿米巴共同培養時，即使沒有與棘阿米巴接觸，也會使得細胞呈現皺縮且漂浮的情形。在本篇研究中，經由穿透式電子顯微鏡與奈米粒子追蹤分析技術等方法學，發現棘阿米巴會產生類外泌體囊泡(exosome-like vesicles;EVs)，我們推測類外泌體囊泡會攜帶特定的分子例如：蛋白質和其他生物分子，而使目標細胞發生一些改變。為了釐清這些囊泡的功能特性，我們自外泌性分泌性產物中純化分離了類外泌體囊泡並且與細胞進行共同培養，透過固定影像擴時攝影顯示，這些由寄生蟲分泌的囊泡會內化至細胞中，並且使得細胞生長受到干擾。接著，利用蛋白質體學技術，分析棘阿米巴分泌的類外泌體囊泡中共鑑定出的130種蛋白質，由生物資訊分析的結果顯示，這些蛋白質主要是酵素類，如：水解酶和氧化還原酶。此外，棘阿米巴所分泌的類外泌體囊泡具有免疫調節能力，誘發發炎類細胞激素，如：IL-6、IL-12的mRNA表達量上升。簡而言之，我們的發現提供了類外泌體囊泡於非接觸介導的棘阿米巴致病機轉與寄生蟲和宿主間的調節作用有了更清楚的理解。

In this study, we discover that Acanthamoeba produced exosome-like vesicles (EVs) which are present in the extracellular excretory-secretory products by using the combination methodologies including transmission electron microscopy and NanoSight. We suggest that the cargo molecules within EVs such as proteins and other biomolecules could make some alterations in the targeted cells. In order to examine the functional properties of these vesicles, we purified the EVs from excretory-secretory products and co-cultured with the cells. Time-lapse images show that these parasite-derived vesicles were internalized and caused cells disruption. Next, we described the prospects for targeting by proteomic profiling. A total of 130 proteins were identified in Acanthamoeba EVs, and bioinformatics analyses indicated that these proteins were mainly enzymes, such as hydrolases and oxidoreductases. In brief, our findings provide a better understanding of the contact-independent pathogenicity of Acanthamoeba in host-parasite interaction.

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