Sm29 is a protective surface protein from the tegument of lung-stage Schistosoma mansoni. Schistosoma mansoni

Schistosomiasis continues to be a significant public health problem1. Although vaccine development against this disease has experienced more failures than successes, encouraging results have recently been obtained using membrane-spanning protein antigens from the tegument of S. mansoni. Our group recently identified Sm29, an antigen that is predominantly recognized by IgG1 and IgG3 antibodies of resistant patients2. In the present study, we show that Sm29 is located on the surface of adult worms and lung-stage schistosomula. Immunization of mice with recombinant (r) Sm29 engendered 51% reduction in adult worm burdens, 60% reduction in intestinal eggs and 55% reduction in liver granulomas. Protective immunity in mice was associated with high titers of specific IgG1 and IgG2a and elevated production of IFN-?, TNF-a and IL-12. Further, cellular responses of infected schistosomiasis patients to rSm29 consisted of elevated IFN-? and an absence of IL-5. Gene expression analysis of worms recovered from rSm29 vaccinated mice relative to control mice revealed a significant (q< 0.01) down-regulation of 498 genes, while no up-regulation was detected. Among down-regulated genes, many of them encode surface antigens and proteins associated with immune signals suggesting that under immune attack schistosomes reduce the expression of critical surface proteins. This study demonstrates that the membrane-bound Sm29 protein is a new molecule that has great potential as a vaccine candidate against schistosomiasis. Keywords: Schistosoma mansoni gene expression in vaccinated mice Overall design: Two biological samples were used in the study, each used in two arrays (technical replicates with dye swap) and each array containing two replicates of each spot. Overall, there are eight data points data points for each spot. Only cases with more than 4 of 8 points are valid ratios were considered. Value and its respective dye swap value [after changing the log(ratio) signal] were averaged, reducing the data point to four. The average values were than used in the significance testing using SAM (Tusher et al., 2001). The samples were used to get average values using the following combination: 3000139790L with 3000139792L; 3000139790R with 3000139792R; 3000139791L with 3000139795L; 3000139791R with 3000139795R The normalized, averaged dyeswap values are provided in a supplementary file at the foot of the record.

血吸虫病（Schistosomiasis）仍是一项重大公共卫生问题[1]。尽管针对该疾病的疫苗研发失败案例多于成功案例，但近期利用曼氏血吸虫（S. mansoni）体被的跨膜蛋白抗原获得了令人振奋的研究结果。我们团队近期鉴定出Sm29，这是一种主要被抗性患者的免疫球蛋白G1（IgG1）和免疫球蛋白G3（IgG3）抗体识别的抗原[2]。

本研究证实，Sm29定位于成虫和肺期童虫的表面。使用重组Sm29（rSm29）免疫小鼠后，小鼠的成虫荷量降低51%，肠道虫卵数减少60%，肝肉芽肿数量降低55%。小鼠体内的保护性免疫与高滴度的特异性IgG1、IgG2a抗体，以及干扰素-γ（IFN-γ）、肿瘤坏死因子-α（TNF-α）和白细胞介素-12（IL-12）的高水平产生密切相关。此外，感染血吸虫病患者的外周血细胞对rSm29的免疫应答表现为IFN-γ水平升高且无白细胞介素-5（IL-5）的产生。

与对照组小鼠相比，从rSm29免疫小鼠体内回收的血吸虫的基因表达分析显示，共有498个基因显著下调（q<0.01），未检测到任何上调基因。在下调的基因中，多数编码表面抗原及与免疫信号通路相关的蛋白，这提示血吸虫在免疫攻击压力下会下调关键表面蛋白的表达。

本研究证实，膜结合型Sm29蛋白是一种极具潜力的抗血吸虫病疫苗候选分子。

关键词：曼氏血吸虫；免疫小鼠基因表达

研究设计概述：本研究共使用两份生物学样本，每份样本均开展两次基因芯片杂交（采用染料置换的技术重复），每张芯片包含每个探针斑点的两份重复样本。最终每个探针斑点共获得8个数据点。本研究仅纳入8个数据点中有效比值数超过4个的样本。将经过对数比值信号转换后的值及其对应的染料置换值取平均，将每个斑点的数据点数量缩减为4个。随后采用SAM（微阵列显著性分析，Tusher等，2001）方法对平均值进行显著性检验。样本按以下组合获取平均值：3000139790L与3000139792L；3000139790R与3000139792R；3000139791L与3000139795L；3000139791R与3000139795R。经过标准化与平均化处理的染料置换值已上传至本记录末尾的补充文件中。