科學(xué)家發(fā)現(xiàn)導(dǎo)致血吸蟲病的寄生蟲幼蟲和卵能釋放一些糖分子,，這些糖分子能引開免疫系統(tǒng)的注意，讓寄生蟲不被發(fā)現(xiàn),。
這項研究發(fā)表在9月出版的《分子與細(xì)胞蛋白質(zhì)組學(xué)》雜志上,，它可能有助于開發(fā)新的療法或者預(yù)防該病的疫苗。
血吸蟲是由裂體屬吸蟲導(dǎo)致的疾病,，根據(jù)世界衛(wèi)生組織的資料，它影響著非洲,、亞洲和南美洲多達(dá)2億人的健康。當(dāng)人接觸被污染的水源之后,，這種寄生蟲就能穿透人的皮膚從而感染人體,。感染可能導(dǎo)致肝臟損傷、失血和死亡,。
來自英國約克大學(xué)和倫敦帝國理工學(xué)院的科學(xué)家分析了這種寄生蟲幼蟲和卵分泌的糖分子，結(jié)果發(fā)現(xiàn)了很多人體不具有的糖分子,。
約克大學(xué)的Alan Wilson參與了這項研究，他告訴本網(wǎng)站說,，這些糖分子會導(dǎo)致人體強(qiáng)烈的免疫應(yīng)答。Wilson說,，這是很不尋常的，因為通常寄生蟲要躲避宿主的免疫系統(tǒng)?，F(xiàn)在這種情況看上去就像寄生蟲使用糖分子引開免疫系統(tǒng)，從而讓幼蟲和卵不被發(fā)現(xiàn),。
盡管這項研究的前景看好，Wilson說開發(fā)疫苗的努力還沒有產(chǎn)生成果,。他說：“如果我們打算用疫苗打敗這種寄生蟲，我們需要對抗它使用過的所有策略，包括這種‘煙幕彈’策略,。我們的研究給出了這種策略的分子基礎(chǔ)。”
Wilson告訴本網(wǎng)站說,，未來的研究將著眼于成蟲分泌的糖分子。成蟲可以在人類血液中至多生活30年以上,。他說：“很明顯，它必須使用一些非常狡猾的機(jī)制,，從而不被非常不利于它的環(huán)境影響。”
埃及坦塔大學(xué)的醫(yī)學(xué)教授Morad Ahmed Morad告訴本網(wǎng)站說,，這項工作為這種寄生蟲的生命周期提供了一些見解,，而且可能有助于克服疫苗研發(fā)的一些困難,。（農(nóng)博網(wǎng)）
原始出處:
Molecular & Cellular Proteomics 6:1485-1499, 2007.
Glycomics Analysis of Schistosoma mansoni Egg and Cercarial Secretions*,S
Jihye Jang-Lee, Rachel S. Curwen, Peter D. Ashton, Bérangère Tissot, William Mathieson, Maria Panico, Anne Dell,¶, R. Alan Wilson and Stuart M. Haslam,||
From the Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, United Kingdom and Department of Biology, University of York, York YO10 5YW, United Kingdom
The parasitic helminth Schistosoma mansoni is a major public health concern in many developing countries. Glycoconjugates, and in particular the carbohydrate component of these products, represent the main immunogenic challenge to the host and could therefore represent one of the crucial determinants for successful parasite establishment. Here we report a comparative glycomics analysis of the N- and O-glycans derived from glycoproteins present in S. mansoni egg (egg-secreted protein) and cercarial (0–3-h released protein) secretions by a combination of mass spectrometric techniques. Our results show that S. mansoni secrete glycoproteins with glycosylation patterns that are complex and stage-specific. Cercarial stage secretions were dominated by N-glycans that were core-xylosylated, whereas N-glycans from egg secretions were predominantly core-difucosylated. O-Glycan core structures from cercarial secretions primarily consisted of the core sequence Galß13(Galß16)GalNAc, whereas egg-secreted O-glycans carried the mucin-type core 1 (Galß13GalNAc) and 2 (Galß13(GlcNAcß16)GalNAc) structures. Additionally we identified a novel O-glycan core in both secretions in which a Gal residue is linked to the protein. Terminal structures of N- and O-glycans contained high levels of fucose and include stage-specific structures. These glycan structures identified in S. mansoni secretions are potentially antigenic motifs and ligands for carbohydrate-binding proteins of the host immune system
