Lipid contribution to the affinity of antigen association with specific antibodies conjugated to liposomes
Lipid contribution to the affinity of antigen association with specific antibodies conjugated to liposomes
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DOI：
10.1016/j.bbamem.2007.04.007
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发表时间：
2007-07-01
影响因子：
3.4
通讯作者：
McPherson, David D.
中科院分区：
文献类型：
--
作者：
Klegerman, Melvin E.;Huang, Shaoling;McPherson, David D.
免疫脂质体，直接与临床相关的细胞表面分子的抗体，抗体片段或肽，用于特定部位的诊断评估或治疗药物的递送。我们已经开发了与纤维蛋白（原）特异性抗体和Fab片段共价连接的内在回声脂质体（ELIP），用于动脉粥样硬化斑块的超声成像。为了确定脂质体偶联对纤维蛋白原结合分子动力学的影响，我们研究了未偶联和elip偶联抗体分子的热力学特性。利用放射免疫测定法和酶联免疫吸附测定法，从三种温度下获得的数据中得出结合亲和力。热力学函数H度、G度和S度由范霍夫图和状态方程确定。由此产生的功能表明，抗体分子与纤维蛋白原的特异性和非特异性结合都是通过各种分子相互作用发生的，包括亲水性、离子键和氢键机制。抗体和Fab片段的ELIP结合引入了δ H度和δ S度结合的特征变化，这对应于磷脂凝胶-液晶相变对结合的可变贡献。这些观察结果表明，影响抗体-抗原结合强度的反向能量转导可能是免疫脂质体的一个独特特征，对该技术的优化和进一步发展具有实用价值。(c) 2007 Elsevier B.V.版权所有
Immunoliposomes, directed to clinically relevant cell-surface molecules with antibodies, antibody fragments or peptides, are used for site-specific diagnostic evaluation or delivery of therapeutic agents. We have developed intrinsically echogenic liposomes (ELIP) covalently linked to fibrin(ogen)-specific antibodies and Fab fragments for ultrasonic imaging of atherosclerotic plaques. In order to determine the effect of liposomal conjugation on the molecular dynamics of fibrinogen binding, we studied the thermodynamic characteristics of unconjugated and ELIP-conjugated antibody molecules. Utilizing radioimmunoassay and enzyme-linked immunosorbent assay protocols, binding affinities were derived from data obtained at three temperatures. The thermodynamic functions Delta H degrees, Delta G degrees and S degrees were determined from van't Hoff plots and equations of state. The resultant functions indicated that both specific and nonspecific associations of antibody molecules with fibrinogen occurred through a variety of molecular interactions, including hydrophophic, ionic and hydrogen bonding mechanisms. ELIP conjugation of antibodies and Fab fragments introduced a characteristic change in both Delta H degrees and Delta S degrees of association, which corresponded to a variable contribution to binding by phospholipid gel-liquid crystal phase transitions. These observations suggest that a reciprocal energy transduction, affecting the strength of antibody-antigen binding, may be a singular characteristic of immunoliposomes, having utility for optimization and further development of the technology. (c) 2007 Elsevier B.V. All rights reserved.