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Abstract：
The caenogastropod mollusk Littorina littorea is a promising experimental model for comparative studies on host/parasite immune conflict. Several different digenean parasites use L. littorea as the first intermediate host, overcoming snail immune reactions by a wide range of tactics that are radically different among different digenean species and at different developmental parasite stages. The immune system of L. littorea is rather effective against digenean Himasthla elongata invasion, and even successfully established parasite induces a chronic host immune reaction, present at a low but stable level, that may be involved in the selection of derived parasitic clones in long lived self-sustaining infrapopulations (SSI) of rediae. An anti-digenean response in L. littorea is not systemic (non-generalized) yet tissue specific, mostly reliant on cellular rather than humoral reactions. The repertoire of immune pattern-recognizing receptors in the common periwinkle comprises diverse secreted and membrane-attached lectin molecules, as the main drivers of snail immune discrimination of digenean parasites. Comparative studies suggest that the characteristic vulnerability to digenean parasitism of L. littorea, and gastropods in general, is in part due the overall organization of immunity relative to other classes of molluscs, e.g. the immune strategy of bivalves seems to rely on less specific cellular reactions and a more generalized systemic humoral immunity. This difference may arise from the molecular features of the selective retention of their taxon-specific complement-like molecular complexes, which diverged in common ancestors of Bivalvia and Gastropoda.
摘要：
caenogastops软体动物Littorinalittorea是一种有前途的实验模型，可用于宿主/寄生虫免疫冲突的比较研究。几种不同的digenean寄生虫使用L.littorea作为第一个中间宿主，通过广泛的策略克服蜗牛免疫反应，这些策略在不同的双生物种和不同的发育寄生虫阶段是完全不同的。L.littorea的免疫系统对digeneanHimasthlaelongata入侵相当有效，甚至成功建立的寄生虫诱导慢性宿主免疫反应，目前处于较低但稳定的水平，这可能与长寿的自我维持基础设施（SSI）中衍生的寄生克隆的选择有关。Littorea中的抗二基因反应不是全身性的（非全身性的），而是组织特异性的，主要依赖于细胞反应而不是体液反应。常见长春花中的免疫模式识别受体库包括不同的分泌和膜附着的凝集素分子，作为蜗牛免疫识别的主要驱动因素的双生寄生虫。比较研究表明，L.littorea对双生寄生的特征脆弱性，一般的腹足类,部分是由于相对于其他软体动物的整体免疫组织，例如，双壳类的免疫策略似乎依赖于特异性较低的细胞反应和更广泛的全身体液免疫。这种差异可能源于其分类单元特异性补体样分子复合物的选择性保留的分子特征，在Bivalvia和腹足纲的共同祖先中存在分歧。
