Synthesis of fluorescein-labelled O-mannosylated peptides as components for synthetic vaccines: comparison of two synthetic strategies
作者:Margaret A. Brimble、Renata Kowalczyk、Paul W. R. Harris、P. Rod Dunbar、Victoria J. Muir
DOI:10.1039/b712926b
日期:——
Mannose-binding proteins on the surface of antigen-presenting cells (APCs) are capable of recognizing and internalizing foreign agents in the early stages of immune response. These receptors offer a potential target for synthetic vaccines, especially vaccines designed to stimulate T cells. We set out to synthesize a series of fluorescein-labelled O-mannosylated peptides using manual solid phase peptide synthesis (SPPS) on pre-loaded Wang resin, in order to test their ability to bind mannose receptors on human APCs in vitro. A flexible and reliable method for the synthesis of fluorescein-labelled O-mannosylated glycopeptides was desired in order to study their lectin-binding properties using flow cell cytometry. Two synthetic strategies were investigated: incorporation of a fluorescein label into the peptide chain via a lysine side chain ε-amino group at the final stage of standard Fmoc solid phase peptide synthesis or attachment of the fluorescein label to the Nα-amino group of a lysine with further incorporation of a mannosylated peptide unit through the side chain Nε-amino group. The latter strategy proved more effective in that it facilitated SPPS by positioning the growing mannosylated peptide chain further removed from the fluorescein label.
抗原递呈细胞(APC)表面的甘露糖结合蛋白能够在免疫反应的早期阶段识别和内化外来物质。这些受体为合成疫苗,尤其是旨在刺激 T 细胞的疫苗提供了潜在的靶点。我们利用预载王树脂上的手工固相肽合成(SPPS)技术合成了一系列荧光素标记的 O-甘露糖基化多肽,以测试它们在体外与人类 APC 上的甘露糖受体结合的能力。我们需要一种灵活可靠的方法来合成荧光素标记的 O-甘露糖基化糖肽,以便利用流式细胞术研究它们的凝集素结合特性。研究人员研究了两种合成策略:在标准 Fmoc 固相肽合成的最后阶段,通过赖氨酸侧链ε-氨基将荧光素标签掺入肽链;或将荧光素标签附着在赖氨酸的 Nα- 氨基上,再通过侧链 Nε- 氨基进一步掺入甘露糖基化的肽单元。事实证明,后一种策略更有效,因为它能使生长中的甘露糖基化肽链进一步远离荧光素标签,从而促进 SPPS。