Muskus C, Segura I, Oddone R, Turco S J, Leiby D A, Toro L, Robledo S, Saravia N G
Corporación Centro Internacional de Entrenamiento e Investigaciones Médicas, CIDEIM, Call, Colombia.
J Parasitol. 1997 Aug;83(4):671-8.
Glycosylated molecules expressed on the cell surface of Leishmania promastigotes contribute to the outcome of contact between the parasite and its invertebrate and vertebrate hosts. The expression of several such molecules is growth phase dependent. Information on the expression of carbohydrates by Leishmania of the Viannia subgenus (braziliensis complex), a widespread cause of morbidity in the Americas, is fragmentary. We have examined the relationship between growth phase and the expression of glycosylated surface structures in WHO reference strains of 3 species of the Viannia subgenus, i.e., L. panamensis, L. guyanensis, and L. braziliensis. Agglutination with lectins and the monoclonal antibody specific for the repeat unit of L. donovani lipophosphoglycan, CA7AE, distinguished logarithmic and stationary-phase promastigotes of all 3 species. Flow cytometry revealed increased heterogeneity and disparity in the expression of the repeat unit epitope in stationary-as compared to logarithmic-phase promastigotes. Biochemical analyses showed the LPG repeat unit of all 3 species reference strains to be constituted by mannose and galactose with little or no substitution and, hence, to be similar to the LPG of L. donovani. Initial quantitative analyses of L. braziliensis LPG indicated a 10-fold lower quantity of LPG in this species than L. donovani and an increase in the size of LPG in the stationary phase. These findings provide bases for isolating and biologically characterizing phenotypically distinct populations of promastigotes and for identifying molecular determinants of the host parasite-relationship among Leishmania Viannia.
利什曼原虫前鞭毛体细胞表面表达的糖基化分子有助于寄生虫与其无脊椎动物和脊椎动物宿主之间接触的结果。几种此类分子的表达取决于生长阶段。关于维亚尼亚亚属（巴西利什曼原虫复合体）利什曼原虫碳水化合物表达的信息支离破碎，该亚属是美洲发病的广泛原因。我们研究了维亚尼亚亚属3个物种（即巴拿马利什曼原虫、圭亚那利什曼原虫和巴西利什曼原虫）的世界卫生组织参考菌株生长阶段与糖基化表面结构表达之间的关系。用凝集素和针对杜氏利什曼原虫脂磷壁酸重复单元的单克隆抗体CA7AE进行凝集试验，区分了所有3个物种的对数期和稳定期前鞭毛体。流式细胞术显示，与对数期前鞭毛体相比，稳定期前鞭毛体重复单元表位表达的异质性和差异增加。生化分析表明，所有3个物种参考菌株的脂磷壁酸重复单元由甘露糖和半乳糖组成，几乎没有或没有取代，因此与杜氏利什曼原虫的脂磷壁酸相似。对巴西利什曼原虫脂磷壁酸的初步定量分析表明，该物种的脂磷壁酸含量比杜氏利什曼原虫低10倍，且在稳定期脂磷壁酸大小增加。这些发现为分离和生物学表征表型不同的前鞭毛体群体以及鉴定利什曼原虫维亚尼亚亚属宿主-寄生虫关系的分子决定因素提供了依据。
