Antibodies as drug carriers III: design of oligonucleotides with enhanced binding affinity for immunoglobulin G.
Antibodies as drug carriers III: design of oligonucleotides with enhanced binding affinity for immunoglobulin G.
复制标题
抗体作为药物载体 III：设计具有增强的免疫球蛋白 G 结合亲和力的寡核苷酸。
DOI：
10.1007/s11095-004-9017-z
复制
发表时间：
2005
影响因子：
3.7
通讯作者：
Cho,MJ
中科院分区：
文献类型：
--
作者：
Palma,Enzo;Klapper,DavidG;Cho,MJ
No HeadingPurposeTo understand the structural requirements in designing epitope-bearing oligonucleotides with high antibody-binding affinity.MethodsBinding affinity (KA) and stoichiometry (n) of dinitrophenyl (DNP)-derivatized model 27-mer oligonucleotides (ODNs), GGG(AAA)7GGG, to monoclonal anti-trinitrophenyl (TNP) antibodies were determined using isothermal titration calorimetry (ITC). Structural variations were made in the ODNs to assess the effects of antigenic valence, epitope density, inter-epitope linker length, and linker flexibility. Binding isotherms were fitted with a single binding-site model to obtain KAand n, from which changes in Gibbs free energy (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) were derived.ResultsAs expected, ligands displaying increased epitope density showed increases in KA: for example, KAfor (DNP)2-Cys is 3.3-fold greater than that for DNP-Lys. Introduction of multiple DNP groups via long and flexible linkers to one end of the 27-mer ODN resulted in a bivalent behavior with n value of 1. A bivalent ligand, derivatized at both ends with a long and flexible linker, failed to form an immune complex when hybridized to its antisense strand, presumably due to intercalation of the DNP moiety to the double strand. ODNs derivatized with flexible linkers exhibited a higher KAthan those with a rigid linker. Ligands with flexible inter-epitope linkers measuring distances of 110, 60, and 40 Å yielded 13-, 30-, and 13-fold increases in KA, respectively. The combination of these factors; namely, bivalence, flexible inter-epitope linkers, and optimal inter-epitope distance, resulted in an overall 66-fold increase in KA. Thermodynamic analysis of binding indicates that the formation of high-affinity ODN-IgG complexes was a spontaneous and exothermic event, characterized by large negative ΔS°, ΔH°, and ΔG° values.ConclusionsAll four strategies tested during this investigation, namely bivalence, epitope density, inter-epitope linker flexibility, and optimal inter-epitope distance, proved to be useful in improving the binding affinity of DNP-labeled ODNs to anti-TNP IgG. The final ODN design incorporating these strategies will be used in testing the systemic pharmacokinetic advantage gained from complexing such ODNs to IgG.
