Functional analyses of esophageal glands of parasitic nematodes

1.松材线虫幼虫进入寄主后的变化我们发现，这种活性在进入宿主后立即消失，这与皮肤穿透能力的消失有关。除经皮感染性和金属蛋白酶活性外，幼虫的运动能力也发生了剧烈变化。为了确定引起幼虫这些变化的因素，我们将感染幼虫在37℃的无血清培养基中培养3天。我们清楚地证明，根据我们检测的所有参数，感染性幼虫转化为结缔组织幼虫。转化需要温度和营养因素。2.成虫的秘密黏附分子具有很强的粘膜侵袭能力，手术植入的成虫侵入雏鸡小肠证实了这一点。在组织迁移过程中，幼虫开始表达黏附分子，黏附分子在肺粘膜侵袭中起重要作用。3.分泌抗原对宿主免疫系统的影响通常由依赖T细胞的粘膜肥大细胞驱逐出宿主。然而，在IL-5转基因小鼠中，高活性的嗜酸性粒细胞渗入小肠上皮层，并清除了粘膜成虫。研究表明，T细胞抗原激活前依赖IL-18的肥大细胞作用和Th2细胞依赖的肥大细胞作用的协同作用对迅速驱除寄生虫具有重要意义。

1.Changes in Strongyloides venezuelensis larvae upon entry into the hostInfective larvae of S.venezuelensis has a matrix metalloprotease. We found that this activity disappeared right after the entry into the host, which was associated with the disappearance of skin penetration ability. In addition to the percutaneous infectivity and metalloprotease activity, drastic changes in locomotion occurred in larvae. In order to identify factors that caused these changes in larvae, we cultured infective larvae in serum-free culture medium at 37 degrees for 3 days. We clearly demonstrated that infective larvae transformed into connective tissue larvae as judged by all parameters we examined. Trans formation required both temperature and nutritional factors.2.Secreted adhesion molecules of adult wormsAdult worms of S.venezuelensis have a potent mucoal invasion capacity, which was confirmed by surgically implanted adult worms invading into chick small intestine. During tissue migration, larvae started expressing adhesion molecules, which are essentially important in mucosal invasion in the lungs.3.Effets of secreted antigens on host immune systemS.venezuelensis is usually expelled from the host by mucosal mast cells which are T cell-dependent. However, in IL-5 transgenic mice, hyperactivated eosinophils infiltrated into epithelial layer of small intestine and cleared mucosal adult worms. Studies on T cell induction in S. venezuelensis infected mice revealed that collaboration between IL-18-dependent mastocytosis before antigenic activation of T cells, and Th2 cell-dependent mastocytosis is important for prompt parasite expulsion.