Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
Biomaterials. 2012 Oct;33(29):7174-81. doi: 10.1016/j.biomaterials.2012.06.024. Epub 2012 Jul 12.
A hybrid biomimetic system comprising high-molecular-weight, linear copolymer of N-(2-hydroxypropyl)methacrylamide (HPMA) grafted with multiple Fab' fragments of anti-CD20 monoclonal antibody (mAb) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization followed by attachment of Fab' fragments via thioether bonds. Exposure of human non-Hodgkin's lymphoma (NHL) Raji B cells to the multivalent conjugates resulted in crosslinking of CD20 receptors and commencement of apoptosis. Five conjugates with varying molecular weight and valence (amount of Fab' per polymer chain) were synthesized. One of the copolymers contained enzyme degradable peptide sequences (GFLG) in the backbone. The multivalency led to higher avidity and apoptosis induction compared to unconjugated whole mAb. Time-dependent studies showed that the cytotoxicity of conjugates exhibited a slower onset at shorter exposure times than mAb hyper-crosslinked with a secondary Ab; however, at longer time intervals the HPMA copolymer conjugates achieved significantly higher biological efficacies. In addition, study of the relationship between the structure of conjugates and Raji B cell apoptosis revealed that both valency and polymer molecular weight influenced biological activities, while insertion of peptide sequences into the backbone was not a factor in vitro.
一种包含高分子量、接枝有多克隆抗体（mAb）Fab'片段的 N-(2-羟丙基)甲基丙烯酰胺（HPMA）线性共聚物的杂化仿生系统，通过可逆加成-断裂链转移（RAFT）聚合合成，然后通过硫醚键连接 Fab'片段。将人非霍奇金淋巴瘤（NHL）Raji B 细胞暴露于多价缀合物中会导致 CD20 受体交联并启动细胞凋亡。合成了 5 种具有不同分子量和价态（聚合物链上的 Fab'数量）的缀合物。其中一种共聚物在主链中含有可酶降解的肽序列（GFLG）。与未缀合的完整 mAb 相比，多价性导致更高的亲和力和凋亡诱导。时程研究表明，与用二级抗体超交联的 mAb 相比，缀合物的细胞毒性在较短的暴露时间内具有较慢的起始时间；然而，在较长的时间间隔内，HPMA 共聚物缀合物达到了显著更高的生物学功效。此外，研究缀合物的结构与 Raji B 细胞凋亡之间的关系表明，价态和聚合物分子量都影响生物活性，而将肽序列插入主链并不是体外的一个因素。
