Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA.
Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA.
Int J Parasitol Drugs Drug Resist. 2018 Dec;8(3):587-595. doi: 10.1016/j.ijpddr.2018.09.002. Epub 2018 Sep 22.
Mass administration of macrocyclic lactones targets the transmission of the causative agents of lymphatic filariasis to their insect vectors by rapidly clearing microfilariae (Mf) from the circulation. It has been proposed that the anti-filarial action of these drugs may be mediated through the host immune system. We recently developed an in vitro assay for monitoring the attachment to and killing of B. malayi Mf by human neutrophils (PMNs) and monocytes (PBMCs), however, the levels of both cell to worm attachment and leukocyte mediated Mf killing varied greatly between individual experiments. To determine whether differences in an individual's immune cells or the Mf themselves might account for the variability in survival, PMNs and PBMCs were isolated from 12 donors every week for 4 weeks and the cells used for survival assays with a different batch of Mf, thereby keeping donors constant but varying the Mf sample. Results from these experiments indicate that, overall, killing is Mf-rather than donor-dependent. To assess whether ivermectin (IVM) or diethylcarbamazine (DEC) increase killing, Mf were incubated either alone or with immune cells in the presence of IVM or DEC. Neither drug induced a significant difference in the survival of Mf whether cultured with or without cells, with the exception of DEC at 2 h post incubation. In addition, human PBMCs and PMNs were incubated with IVM or DEC for 1 h or 16 h prior to RNA extraction and Illumina sequencing. Although donor-to-donor variation may mask subtle differences in gene expression, principle component analysis of the RNASeq data indicates that there is no significant change in the expression of any genes from the treated cells versus controls. Together these data suggest that IVM and DEC have little direct effect on immune cells involved in the rapid clearance of Mf from the circulation.
大环内酯类药物的大量给药通过从循环中迅速清除微丝蚴（Mf），靶向淋巴丝虫病的病原体传播给它们的昆虫媒介。有人提出，这些药物的抗丝虫作用可能是通过宿主免疫系统介导的。我们最近开发了一种体外测定法，用于监测人中性粒细胞（PMN）和单核细胞（PBMC）对 B. malayi Mf 的附着和杀伤，然而，单个实验之间，细胞与虫体的附着和白细胞介导的 Mf 杀伤水平差异很大。为了确定个体免疫细胞或 Mf 本身的差异是否可以解释存活率的差异，每周从 12 个供体中分离 PMN 和 PBMC，并将细胞用于具有不同批次 Mf 的生存测定，从而保持供体不变，但改变 Mf 样本。这些实验的结果表明，总体而言，杀伤是 Mf 依赖性的，而不是供体依赖性的。为了评估伊维菌素（IVM）或乙胺嗪（DEC）是否增加杀伤，将 Mf 单独孵育或与免疫细胞一起孵育，在存在 IVM 或 DEC 的情况下。无论是否有细胞培养，两种药物都没有诱导 Mf 存活率显著差异，除了 DEC 在孵育后 2 小时。此外，将人 PBMC 和 PMN 与 IVM 或 DEC 孵育 1 小时或 16 小时，然后提取 RNA 并进行 Illumina 测序。尽管供体间的差异可能掩盖了基因表达的细微差异，但 RNASeq 数据的主成分分析表明，与对照相比，处理细胞中没有任何基因的表达发生显著变化。这些数据表明，IVM 和 DEC 对参与从循环中快速清除 Mf 的免疫细胞几乎没有直接影响。
