Functional analyses of esophageal glands of parasitic nematodes

1.委内瑞拉圆线虫幼虫进入宿主后的变化委内瑞拉圆线虫感染性幼虫具有基质金属蛋白酶。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。除了经皮感染性和金属蛋白酶活性，在运动发生剧烈变化的幼虫。为了确定引起幼虫这些变化的因素，我们将感染性幼虫在无血清培养基中于37 ℃培养3天。我们清楚地表明，感染性幼虫转化为结缔组织幼虫判断，我们检查的所有参数。2.成虫分泌的粘附分子委内瑞拉沙门氏菌成虫具有较强的粘膜侵袭能力，通过手术植入的蠕虫侵入鸡小肠证实了这一点。在组织迁移过程中，幼虫开始表达粘附分子，这些粘附分子在肺的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委内瑞拉丝虫通常通过依赖于T细胞的粘膜肥大细胞排出宿主。而在IL-5转基因小鼠中，高活化的嗜酸性粒细胞浸润到小肠上皮层并清除粘膜蠕虫。S. venezuelensis感染的小鼠揭示了在T细胞的抗原活化之前IL-18依赖性肥大细胞增多症和Th 2细胞依赖性肥大细胞增多症之间的协作对于迅速排出寄生虫是重要的。

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.