BINDING OF PRES1 PEPTIDES OF HBSAG TO HUMAN LIVER IN THE PRESENCE OF ANTI-PRES1

在抗 PRES1 存在的情况下 HBSAG 的 PRES1 肽与人肝脏的结合

• 批准号: 3770454
• 负责人: Z P GUO
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3770454
• 关键词: antibody receptor; antireceptor antibody; antiviral antibody; cell membrane; chemical binding; gene mutation; hepatitis B antigens; human tissue; immune complex; immunoglobulin G; immunoglobulin structure; laboratory rabbit; liver cells; monoclonal antibody; monocyte; neutralizing antibody; pepsin; peptides; recombinant proteins

As described in the previous annual reports, we expressed and purified two recombinant preS1 peptides (rpreS1) of hepatitis B surface antigen, i.e., a 91 amino acid (AA) wild-type peptide and a tyrosine-substituted 90 AA mutant peptide. Binding of either 125I-labeled rpreS1 peptide to a crude plasma membrane (pm) preparation from an autopsied human liver specimen was not significant. However, in the presence of anti-rpreS1 (which was produced by immunizing rabbits with the wild-type rpreS1 but recognizes both wild-type and mutant peptides), a high affinity binding was observed. The binding to pm appeared to be due to immune complexes formed between rpreS1 and anti-rpreS1. This Ag-Ab binding reached equilibrium within 20 minutes at room temperature. The binding was saturable with labeled immune complexes at 10-9 M when the pm preparation was kept constant. When the labeled rpreS1 was kept constant, increasing levels of either pm or anti- rpreS1 enhanced the binding. Neither hepG2 cells nor monocytes isolated from human blood showed any binding. The binding was blocked when pm was preincubated with unlabeled rpreS1 but not with anti-rpreS1. However, no binding was observed with (Fab')2 produced by digesting the intact IgG of anti-rpreS1 with pepsin. Thus, the binding appeared to be Fc receptor mediated. Preliminary results indicated that preincubation of pm with monoclonal antibodies to FcRI, FcRII and FcRIII had no effect on the binding of the labeled rpreS1-anti-rpreS1 complexes to pm. We have yet to determine whether such binding is specific to human hepatocytes. The significance of such binding of preS1 in the presence of its antibody remains to be investigated.

如前几份年度报告所述，我们表达并纯化了两个 乙型肝炎B表面抗原的重组preS 1肽（rpreS 1），即， 91个氨基酸（AA）的野生型肽和酪氨酸取代的90个AA 突变肽 125 I标记的rpreS 1肽与粗品的结合 从尸检的人肝样本制备质膜（PM）， 不显著 然而，在存在抗rpreS 1（ 通过用野生型rpreS 1免疫兔子产生，但识别 野生型和突变体肽），观察到高亲和力结合。 与pm的结合似乎是由于免疫复合物之间形成 rpreS 1和抗rpreS 1。 这种Ag-Ab结合在20 在室温下保持10分钟。 结合是饱和的标记免疫 当pm制备保持恒定时，在10-9 M下制备复合物。 当 标记的rpreS 1保持恒定，增加pm或抗- rpreS 1增强了这种结合。 未分离hepG 2细胞和单核细胞 显示出任何结合力 当pm被阻止时， 用未标记的rpreS 1预孵育，但不用抗rpreS 1预孵育。 但没有 观察到与通过消化完整IgG产生的（Fab '）2的结合。 抗rpreS 1和胃蛋白酶。 因此，结合似乎是Fc受体 调解。 初步结果表明，PM与 抗FcRI、FcRII和FcRIII的单克隆抗体对FcRI、FcRII和FcRIII的表达没有影响。 标记的rpreS 1-抗rpreS 1复合物与pm的结合。 我们还没有 确定这种结合是否对人肝细胞特异。 的 preS 1在其抗体存在下的这种结合的意义 仍有待调查。