Gruden-Movsesijan Alisa, Petrovic Miomir, Sofronic-Milosavljevic Ljiljana
Institute for the Application of Nuclear Energy, 11080 Belgrade, Serbia and Montenegro.
Parasite Immunol. 2003 Nov-Dec;25(11-12):545-52. doi: 10.1111/j.0141-9838.2004.00665.x.
Complex and variable glycoconjugates presented by parasitic nematodes during infection are very important in the host-parasite interplay. Predominantly carbohydrate-rich antigens are involved in the stimulation and modulation of the stage-specific immune response of the host. The non-specific innate immune system, however, acts as the first line of host defence against pathogens, before the appearance of antigen-specific responses. The functional entities of the innate system are lectins that recognize the surface ligands of pathogens: mannan-binding lectin (MBL) is a key recognition element involved in binding oligosaccharide structures exposed on microorganisms. In the present study we investigated whether MBL binds to the parasitic nematode Trichinella spiralis (T. spiralis). Since the parasite is coated with mannose-containing glycans, these structures could represent potential ligands for MBL and contribute to activation of the innate immune response of the host. Histochemical staining revealed MBL on the surface and internal organs of T. spiralis muscle larvae. MBL bound in a mannose-inhibitable manner to both crude extracts of T. spiralis muscle larvae and larvae excretory/secretory products. Western blot analyses showed that MBL recognized glycoproteins from all stages of T. spiralis. In vitro complement activation assays suggested that MBL is capable of fixing complement components on T. spiralis crude extract coated plates and activating the complement cascade through the 'lectin pathway'.
寄生线虫在感染过程中呈现的复杂且多样的糖缀合物在宿主与寄生虫的相互作用中非常重要。富含碳水化合物的主要抗原参与宿主阶段特异性免疫反应的刺激和调节。然而，非特异性先天免疫系统在抗原特异性反应出现之前，作为宿主抵御病原体的第一道防线。先天系统的功能实体是识别病原体表面配体的凝集素：甘露糖结合凝集素（MBL）是参与结合微生物上暴露的寡糖结构的关键识别元件。在本研究中，我们调查了MBL是否与寄生线虫旋毛虫（T. spiralis）结合。由于该寄生虫被含甘露糖的聚糖包被，这些结构可能代表MBL的潜在配体，并有助于激活宿主的先天免疫反应。组织化学染色显示MBL存在于旋毛虫肌幼虫的表面和内部器官。MBL以甘露糖可抑制的方式与旋毛虫肌幼虫的粗提物和幼虫排泄/分泌产物结合。蛋白质印迹分析表明MBL识别旋毛虫所有阶段的糖蛋白。体外补体激活试验表明，MBL能够在包被有旋毛虫粗提物的平板上固定补体成分，并通过“凝集素途径”激活补体级联反应。
