Visceral leishmaniasis (VL) is an infectious disease caused by parasitic protozoa of the genus Leishmania and manifests clinical symptoms such as splenomegaly, hepatomegaly, anemia, and fever. It has previously been shown that B-cell-activating factor (BAFF) is involved in splenomegaly during VL. Although BAFF is known to be expressed by a variety of cells, the mechanism of elevated BAFF expression in VL is not clear. In this study, we aimed to identify BAFF-producing cells in the spleens of mice infected with Leishmania donovani. Splenocytes of L. donovani-infected mice showed elevated BAFF expression compared to that of naive mice. In the infected spleen, the number of both CD11b+ and F4/80+ cells increased, and the major BAFF-producing cells were CD11b+ cells, which did not serve as host cells of Leishmania. Immunohistochemical/immunofluorescent staining of spleens of infected mice revealed that the increased CD11b+ cells were primarily MRP14+ mononuclear cells. Together, these results suggest the increased BAFF expression in the spleen of L. donovani-infected mice involves a recruitment of inflammatory macrophages distinct from host macrophages for the parasites.

中文翻译：

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感染杜氏利什曼原虫的小鼠脾脏中炎症性 CD11b+ 巨噬细胞产生 BAFF

内脏利什曼病（VL）是由利什曼原虫属寄生原虫引起的传染病，表现为脾肿大、肝肿大、贫血、发热等临床症状。此前已有研究表明，B 细胞激活因子 (BAFF) 与 VL 期间的脾肿大有关。尽管已知 BAFF 在多种细胞中表达，但 VL 中 BAFF 表达升高的机制尚不清楚。在这项研究中，我们的目的是鉴定感染杜氏利什曼原虫的小鼠脾脏中产生 BAFF 的细胞。与初始小鼠相比，杜氏乳杆菌感染小鼠的脾细胞表现出 BAFF 表达升高。在感染的脾脏中，CD11b+和F4/80+细胞的数量均增加，并且主要产生BAFF的细胞是CD11b+细胞，其不作为利什曼原虫的宿主细胞。对感染小鼠的脾脏进行免疫组织化学/免疫荧光染色显示，增加的 CD11b+ 细胞主要是 MRP14+ 单核细胞。总之，这些结果表明杜氏乳杆菌感染小鼠脾脏中 BAFF 表达的增加涉及与寄生虫宿主巨噬细胞不同的炎症巨噬细胞的募集。