Leishmania (Viannia) braziliensis is the main agent of mucocutaneous Leishmaniasis, a neglected tropical disease that affects thousands of people in Brazil. It has been shown that complement plays a critical role at early stages of Leishmania infection and that is involved in the invasion of macrophages by the promastigotes. Ficolins and collectins are soluble pattern recognition and triggering molecules of the lectin complement pathway. We investigated here whether lectin pathway activators ficolin-1, ficolin-2, ficolin-3 and CL-11 bind to live L. braziliensis promastigotes in vitro. Promastigote forms in the stationary growth phase were incubated with normal human serum (NHS) or recombinant ficolins 1, 2 and 3, MBL and CL-11, and protein binding was evaluated by confocal microscopy and flow cytometry. Ficolins 1, 2 and 3, MBL and CL-11 were able to bind to the surface of live promastigotes after incubation with either NHS or recombinant proteins. A partial inhibition by N-acetyl-d-glucosamine characterizing the participation of acetylated groups in the deposition of ficolins and CL-11 to glycoconjugates on the surface of L. braziliensis was observed. These evidences highlight a role for the lectin pathway in the innate response to L. braziliensis.

巴西利什曼原虫（Viannia）是粘膜皮肤利什曼病的主要病原体，这是一种被忽视的热带疾病，影响着巴西数千人。研究表明，补体在利什曼原虫感染的早期阶段起着至关重要的作用，并且参与前鞭毛体对巨噬细胞的侵袭。 Ficolins 和collectins 是可溶性模式识别和凝集素补体途径的触发分子。我们在此研究了凝集素途径激活剂 ficolin-1、ficolin-2、ficolin-3 和 CL-11 是否在体外与活体巴西乳杆菌前鞭毛体结合。将处于稳定生长期的前鞭毛体形式与正常人血清 (NHS) 或重组丝胶蛋白 1、2 和 3、MBL 和 CL-11 一起孵育，并通过共聚焦显微镜和流式细胞术评估蛋白质结合。 Ficolins 1、2 和 3、MBL 和 CL-11 在与 NHS 或重组蛋白一起孵育后能够结合到活前鞭毛体的表面。观察到 N-乙酰基-d-葡萄糖胺的部分抑制，其特征在于乙酰化基团参与纤维胶蛋白和 CL-11 在巴西乳杆菌表面的糖缀合物的沉积。这些证据强调了凝集素途径在对巴西乳杆菌的先天反应中的作用。