Odontogenic keratocysts (OKCs) are jaw cystic lesions which are characterized by local invasion and high recurrence rate. The majority of OKCs are exposed to microorganisms and occur along with focal inflammatory infiltrates. Cyst fluids are biological fluids that contain a large content of cytokines and immune globulins. Inhibitory receptor such as programmed death receptor 1 (PD-1) and its ligand programmed death-ligand 1 (PD-L1), which can induce a coinhibitory signal in activated T cells, plays a vital role in the differentiation, exhaustion and apoptosis of T cells. Cell derived microvesicles, carrying a cargo of functional proteins, nucleic acids and lipids, are important communication tools in the development of diseases. However, the expression of PD-L1 in OKCs tissues and whether PD-L1 could be carried by microvesicles are unexplored. Presently, we have isolated cyst fluid microvesicles and identified cell derived PD-L1⁺ cyst fluid microvesicles. PD-L1 was located in the membrane of the cyst fluid microvesicles. The main cellular origins of PD-L1⁺ cyst fluid microvesicles were dendritic cells followed by lymphocytes. Elevated PD-L1⁺ cyst fluid microvesicles were detected in the OKCs compared with dentigerous cysts. Isolated cyst fluid microvesicles could bind to the membrane of activated CD8 T cells and inhibit proliferation of stimulated peripheral blood CD8 T cells. In conclusion, the present study suggests that elevated PD-L1⁺ cyst fluid microvesicles might be related with the cyst development of OKCs.

中文翻译：

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非综合征牙源性角化囊肿的囊液中PD-L1 +微泡的体外评估。

牙源性角化囊肿（OKCs）是颌骨囊性病变，其特征在于局部浸润和高复发率。大多数OKC暴露于微生物，并与局灶性炎症浸润一起发生。囊肿液是含有大量细胞因子和免疫球蛋白的生物液。抑制性受体，如程序性死亡受体1（PD-1）及其配体程序性死亡配体1（PD-L1），可在活化的T细胞中诱导共抑制信号，在肝癌细胞的分化，衰竭和凋亡中起着至关重要的作用。 T细胞。携带大量功能蛋白，核酸和脂质的细胞衍生微囊泡是疾病发展中的重要交流工具。然而，尚未探索PDC-L1在OKC组织中的表达以及PD-L1是否可以被微囊泡携带。⁺囊液微泡。PD-L1位于囊液微泡的膜中。PD-L1 ⁺囊肿液微泡的主要细胞起源是树突状细胞，其次是淋巴细胞。与齿状囊肿相比，在OKC中检测到PD-L1 ⁺囊肿液微泡升高。分离的囊肿液微泡可与活化的CD8 T细胞膜结合并抑制受刺激的外周血CD8 T细胞增殖。总之，本研究提示PD-L1 ⁺囊肿液微泡升高可能与OKCs的囊肿发展有关。