Vierbuchen M, Uhlenbruck G, Hanisch F G, Müller W E, Ortmann M, Fischer R
Institute of Pathology, University of Cologne, Federal Republic of Germany.
J Histochem Cytochem. 1991 Apr;39(4):491-505. doi: 10.1177/39.4.2005375.
We applied a peroxidase-antiperoxidase technique to study the distribution pattern and binding characteristics of the lectin from the marine sponge Geodia cydonium (Geodia cydonium agglutinin; GCA) in various human tissues. This lectin has been shown to possess a broad reactivity, but there was a distinct distribution of binding sites within the different organs. In the histochemical system GCA displayed no blood group specificity and labeled red blood cells, the vascular endothelium, and epithelial cells showing blood group antigen expression independent of the ABH blood group status. However, inhibition of GCA reactivity by simple sugars and complex carbohydrates demonstrated tissue-specific differences of lectin binding related to the ABH blood group status of the tissue and revealed information on the structural requirements of the histological lectin binding site. Tissues that totally lacked blood group antigens or that expressed only the H-antigen disclosed a GCA reactivity which was completely inhibited by lactose. In contrast, tissues that expressed blood group A- or blood group B-antigen exhibited a lactose-resistant lectin binding which was inhibited only by water-soluble blood group substance A from peptone A and by bovine glycophorin but not by other complex carbohydrates, including human glycophorin and human asialoglycophorin. Competitive inhibition studies in situ revealed that GCA binding was not inhibited by blood group type I/II carbohydrate sequence-specific lectins or by lectins with other sugar specificities. Inhibition by lactose of GCA binding to some histological sites indicates that the binding site consists of a beta-linked galactose-containing disaccharide. However, periodate oxidation of tissue sections had no effect on lectin binding, pointing to a subterminal location of the relevant sequence. The results obtained from inhibition studies with simple saccharides and complex carbohydrates in relation to the expression of ABH blood group antigens suggest a complex lectin combining site(s) in histological specimens. The lectin may possess either one binding site with a range of affinities for different carbohydrates (besides beta-linked disaccharides the GCA binding site accommodates to carbohydrate determinants carrying the blood group A or blood group B determinant), or may possess two different binding sites. Besides an acceptor site for beta-linked disaccharides, an additional binding site may exist accommodating to extended carbohydrate sequences related to A or B blood group structures. In conclusion, GCA represents a blood group-nonspecific lectin whose binding affinities are determined by the ABH blood group status of the tissue.
我们应用过氧化物酶-抗过氧化物酶技术来研究海洋海绵地穴海绵（地穴海绵凝集素；GCA）凝集素在各种人体组织中的分布模式和结合特性。已证明这种凝集素具有广泛的反应性，但在不同器官内结合位点的分布存在明显差异。在组织化学系统中，GCA不显示血型特异性，可标记红细胞、血管内皮细胞以及表达血型抗原的上皮细胞，且与ABH血型状态无关。然而，单糖和复合碳水化合物对GCA反应性的抑制表明，凝集素结合存在与组织ABH血型状态相关的组织特异性差异，并揭示了组织学凝集素结合位点的结构要求信息。完全缺乏血型抗原或仅表达H抗原的组织显示出GCA反应性，该反应性可被乳糖完全抑制。相反，表达A型或B型血型抗原的组织表现出对乳糖具有抗性的凝集素结合，仅被来自蛋白胨A的水溶性血型物质A和牛血型糖蛋白抑制，而不被其他复合碳水化合物抑制，包括人血型糖蛋白和人去唾液酸血型糖蛋白。原位竞争抑制研究表明，GCA结合不受I/II型碳水化合物序列特异性凝集素或具有其他糖特异性的凝集素抑制。乳糖对GCA与某些组织学位点结合的抑制表明，结合位点由一个含β-连接半乳糖的二糖组成。然而，组织切片的高碘酸盐氧化对凝集素结合没有影响，表明相关序列位于亚末端位置。从与ABH血型抗原表达相关的单糖和复合碳水化合物抑制研究中获得的结果表明，在组织学标本中存在复杂的凝集素结合位点。凝集素可能具有一个对不同碳水化合物具有一系列亲和力的结合位点（除了β-连接的二糖外，GCA结合位点还可容纳携带A型或B型血型决定簇的碳水化合物决定簇），或者可能具有两个不同的结合位点。除了β-连接二糖的受体位点外，可能还存在一个额外的结合位点，可容纳与A或B血型结构相关的延伸碳水化合物序列。总之，GCA代表一种血型非特异性凝集素，其结合亲和力由组织的ABH血型状态决定。
