The current study aimed to detect the complement-binding proteins in the excretory-secretory (ES) products of adult filarial parasite Setaria equina (SeqES). Tests for complement activation pathways (CH50 and APH50 ) in normal human serum (NHS) after incubation with SeqES were performed. Quantitative detection of complement activation products like C3d and sC5b-9 by ELISA in inulin-activated NHS before and after addition of SeqES was estimated. Immunoblotting for 1D and 2D electrophoresed SeqES were performed for detection of C9-binding protein. MALDI mass sequencing and multiple sequence alignment were performed for identification of the protein. The results showed an inhibitory effect of SeqES for complement activation pathways. This was confirmed by an obvious reduction in C3d and sC5b-9 in inulin-activated NHS. Immunoblotting showed the reaction of a protein at 21 kDa with human C9. The latter protein was identified as OV-16 based on MALDI mass sequencing and multiple sequence alignment. In conclusion, S equina OV-16 is the complement regulatory protein by its ability to bind C9 and inhibit the classical and alternative pathways of complement activation. This protein can be used as a target for therapeutic treatment or as an anti-inflammatory agent in human diseases.

中文翻译：

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马尾Setaria马分泌物分泌物中补体9结合蛋白的鉴定。

当前的研究旨在检测成年丝虫寄生马狗（Setaria equina，SeqES）的分泌-分泌（ES）产物中的补体结合蛋白。与SeqES孵育后，进行了正常人血清（NHS）中补体激活途径（CH50和APH50）的测试。估计在添加​​SeqES之前和之后，在菊粉激活的NHS中通过ELISA定量检测补体激活产物（例如C3d和sC5b-9）。一维和二维电泳的SeqES进行了免疫印迹，以检测C9结合蛋白。进行MALDI质谱测序和多序列比对以鉴定蛋白质。结果显示SeqES对补体激活途径的抑制作用。菊糖激活的NHS中C3d和sC5b-9的明显减少证实了这一点。免疫印迹显示21 kDa的蛋白质与人C9反应。基于MALDI质量测序和多序列比对，后者被鉴定为OV-16。综上所述，马马OV-16具有结合C9并抑制补体激活经典途径和替代途径的能力，是补体调节蛋白。该蛋白可用作人类疾病的治疗靶标或抗炎剂。