Effective Production of Monoclonal Antibodies Against Low Immunogenic Substances

通常认为，天然丰富的抗原如膜脂和碳水化合物，或具有物种间保守氨基酸序列的低分子量肽，免疫原性较低，并且难以获得针对这些物质的单克隆抗体。在本研究中，我们建立了有效生产针对这些低免疫原性材料的单克隆抗体的方法。1）磷脂抗原：我们采用基于磷脂抗原直接免疫脾脏的系统在正常受试者中诱导抗磷脂抗体，并且发现该方法有效地诱导IgG同种型的抗磷脂抗体。建立了一系列抗磷脂酰丝氨酸和磷脂酰胆碱的单克隆抗体。对抗磷脂单克隆抗体的反应性和结构的分析为抗磷脂抗体在所谓的“抗磷脂抗体综合征”中的病因学提供了新的见解。2）对大豆脂质的免疫应答：最近的分析表明大豆脂质是食物过敏的最强诱导物之一。在研究对大豆脂质的免疫应答的过程中，我们发现针对特定血清组分的自身抗体经常由脂质的口服或脾内施用诱导。3）蛋白质抗原：脾内免疫和8-巯基胍基核苷作为佐剂的组合提供了一种有用的方法来产生针对低免疫原性蛋白质抗原的单克隆抗体。用这种方法，我们首次成功地制备了抗磷脂酶的单克隆抗体。

It is generally accepted that naturally abundant antigens such as membrane lipids and carbohydrates, or low molecular weight peptides with conserved amino acid sequences among species, are less immunogenic and it has been difficult to obtain monoclonal antibodies against these substances. In this study, we have established the methods for the effective production of monoclonal antibodies against these low immunogenic materials.1) Phospholipid antigens :We employed a system based on the direct immunization of phospholipid antigens into spleen to induce anti-phospholipid antibodies in normal subjects, and found that anti-phospholipid antibodies of IgG isotypes were effectively induced by the method. A series of monoclonal antibodies against phosphatidylserine and phosphatidylcholine were established. Analyses of reactivities and structures of anti-phospholipid monoclonal antibodies have provided a new insight into the etiology of anti-phospholipid antibodies in the so called "anti-phospholipid antibody syndromes".2) Immune response against soy bean lipids :Recent analyses have suggested that soy bean lipid is one of the strongest inducer of food allergies. In the course of studying the immune response to soy bean lipids, we found that auto antibodies against a particular serum component were frequently induced by the oral or intrasplenic administration of the lipids. Mechanism of the induction and etiology of this unique autoantibody is now under investigation.3) Protein antigens :Combination of intrasplenic immunization and 8-mercaptogua-nosine as an adjuvant have provided a useful method to produce monoclonal antibodies against low immunogenic protein antigens. By this method, we for the first time succeeded in producing monoclonal antibodies against phospholipases.