Department of Biochemistry and Immunology, Biological Sciences Institute, Federal University of Minas Gerais Minas Gerais, Belo Horizonte, MG, Brazil.
Parasitology. 2010 Jun;137(7):1079-88. doi: 10.1017/S0031182009991387. Epub 2009 Oct 16.
Proteins associated with the schistosome tegument are of great importance for the development of new intervention strategies since they may be exposed on the surface of the parasite. Herein, we have isolated a cDNA clone encoding for the Schistosoma mansoni SmIg and its recombinant protein was tested as a potential vaccine candidate. Initially, its amino acid sequence was analysed by bioinformatics and shown to possess an N-terminal signal peptide, a C-terminal transmembrane helix, 4 glycosylation sites, an immunoglobulin conserved domain and 73% similarity with a hypothetical S. japonicum protein of unknown function. SmIg was produced by E. coli as a recombinant protein (rSmIg) and its protective effectiveness was evaluated against S. mansoni infection with 100 cercariae in a murine model. Mice immunized with rSmIg induced an immune response characterized by dominant IgG1 isotype and significant levels of IFN-gamma, TNF-alpha, IL-10 and IL-4. Although immunogenic, the recombinant vaccine failed to induce worm burden reduction when compared to the infected control group. However, rSmIg-immunized mice had significant reductions of liver granuloma volume and fibrosis content by 31.8% and 49%, respectively. In conclusion, SmIg is a new tegument protein from S. mansoni that plays an important role in reducing pathology induced by parasite infection.
与血吸虫体被相关的蛋白质对于开发新的干预策略非常重要，因为它们可能暴露在寄生虫的表面。在此，我们分离了一个编码曼氏血吸虫 SmIg 的 cDNA 克隆，并测试了其重组蛋白作为一种潜在的疫苗候选物。最初，通过生物信息学分析其氨基酸序列，发现它具有 N 端信号肽、C 端跨膜螺旋、4 个糖基化位点、免疫球蛋白保守结构域和与功能未知的日本血吸虫蛋白 73%的相似性。SmIg 由大肠杆菌作为重组蛋白（rSmIg）产生，并在小鼠模型中用 100 条尾蚴评估其对曼氏血吸虫感染的保护效果。用 rSmIg 免疫的小鼠诱导了以 IgG1 同型为主的免疫应答，并产生了显著水平的 IFN-γ、TNF-α、IL-10 和 IL-4。尽管具有免疫原性，但重组疫苗在降低虫体负荷方面并未优于感染对照组。然而，rSmIg 免疫的小鼠的肝肉芽肿体积和纤维化含量分别减少了 31.8%和 49%。总之，SmIg 是曼氏血吸虫的一种新的体被蛋白，在减轻寄生虫感染引起的病理学方面发挥着重要作用。
