Development of a simple procedure for the isolation of secretory IgA by lectin affinity chromatography and its clinical application.

从菠萝蜜种子（Artocarpus integrfolia）中提取的一种凝集素首次被报道为lga特异性结合凝集素。我们收集了来自菲律宾、新加坡、日本等不同国家的几批菠萝蜜种子，发现菲律宾的一批种子特异性结合了LgA1亚类的人类LgA，而不结合LgA2亚类。由LgA1特异性凝集素（jacalin-P）制成的亲和柱可用于LgA1亚类分泌性LgA的分离。该柱还用于从常规纯化的人乳LgA中分离分泌性LgA中的LgA1和LgA2。对jacalin-P的糖特异性分析得出结论，在LgA1铰链中存在但在LgA2亚类中不存在的低聚糖Gal 1-3GalNAc负责凝集素的LgA1特异性。在除jacalin-P以外的凝集素中，我们发现一种凝集素可以结合除LgA以外的所有免疫球蛋白。进一步分析该凝集素（jacalin-H）表明，它还结合聚集的LgG和免疫复合物。使用jacalin-H亲和柱有效地从γ -球蛋白制剂中去除聚集的LgG和免疫复合物以及免疫球蛋白，而不是天然单体LgG。这样处理的人γ -球蛋白制剂没有抗补体活性，将适用于各种免疫缺陷患者的安全免疫球蛋白制剂，包括选择性免疫球蛋白缺乏症，因为它仅由天然单体LgG组成。

A lectin from jackfruit seeds ( Artocarpus integrifolia ) was first reported to be an LgA-specific binding lectin. We have collected several batches of jackfruit seeds from different countries, including the Phillippines, Singapore and Japan, and found that a batch of seeds from the Phillippines specifically bound human LgA of LgA1 subclass but not LgA2 subclass. The affinity column made from the LgA1-specific lectin ( jacalin-P ) could be used for the isolation of secretory LgA of LgA1 subclass. This column was also used for the separation of LgA1 and LgA2 of secretory LgA from conventionally purified human milk LgA. Analysis of sugar specificity of jacalin-P led to a conclusion that the oligosaccharide, Gal 1-3GalNAc, which is present in LgA1 hinge but is absent in LgA2 subclass, was responsible for the LgA1-specificty of the lectin.Among the lectins other than the jacalin-P, we found a lectin that bound every immunoglobulin other than LgA. Further analysis of this lectin ( jacalin-H ) disclosed that it also bound aggregated LgG and immune-complex. The use of jacalin-H affinity column efficiently removed the aggregated LgG and immune-complex as well as immunoglobulins other than native monomeric LgG from gamma-globulin preparations. The human gamma-globulin preparation thus treated was free from anti-complementary activity and will be applicable as a safe immunoglobulin preparation for various immune-deficient patients, including selective immunoglobulin deficiency, since it consisted of only native monomeric LgG.