Leishmaniasis is one of the most significant of the neglected tropical diseases, with 350 million people in 98 countries worldwide living at risk of developing one of the many forms of the disease. During the transmission of the parasite from its vector to the vertebrate host, neutrophils are rapidly recruited to the site of the sandfly bite. Using different strategies, neutrophils can often kill a large number of parasites. However, some parasites can resist neutrophil-killing mechanisms and survive until macrophage arrival at the infection site. One of the strategies for neutrophil-mediated killing is the production of neutrophil extracellular traps (NETs). Because of its ecto-localized nuclease activity, the enzyme 3’-nucleotidase/nuclease (3’NT/NU), present in different Leishmania species, was recently identified as part of a possible parasite escape mechanism from NET-mediated death. Previous studies showed that 3’NT/NU also plays an important role in the establishment of Leishmania infection by generating extracellular adenosine that favors the parasite and macrophage interaction. This study aims to deepen the knowledge about 3’NT/NU, mainly with respect to its nuclease activity that is little studied in the current literature. For this, we cloned, expressed and purified the recombinant La3'NT/NU and have confirmed its contribution to the parasite escape from NET-mediated killing.

利什曼病是最重要的被忽视的热带病之一，全球98个国家/地区的3.5亿人处于发展多种疾病之一的危险之中。在寄生虫从其载体传播到脊椎动物宿主的过程中，嗜中性粒细胞被迅速募集到the蝇叮咬的部位。使用不同的策略，中性粒细胞通常可以杀死大量的寄生虫。但是，某些寄生虫可以抵抗中性粒细胞杀伤机制，并且可以存活直到巨噬细胞到达感染部位。中性粒细胞介导的杀伤的策略之一是中性粒细胞胞外捕获物（NETs）的产生。由于其胞外定位的核酸酶活性，存在于不同利什曼原虫中的3'-核苷酸酶/核酸酶（3'NT / NU）酶物种，最近被确定为可能的寄生虫逃逸机制从NET介导的死亡的一部分。先前的研究表明3'NT / NU在利什曼原虫感染的建立中也起着重要作用，其产生的细胞外腺苷有利于寄生虫和巨噬细胞的相互作用。这项研究旨在加深关于3'NT / NU的知识，主要是关于3'NT / NU的核酸酶活性，这在当前文献中很少研究。为此，我们克隆，表达和纯化了重组La3'NT / NU，并证实了其对NET介导的杀伤过程中寄生虫逃逸的贡献。