Abdelhameed Ali Saber, Adams Gary G, Morris Gordon A, Almutairi Fahad M, Duvivier Pierre, Conrath Karel, Harding Stephen E
National Centre for Macromolecular Hydrodynamics, University of Nottingham, Sutton Bonington LE12 5RD, UK.
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.
Sci Rep. 2016 Feb 26;6:22208. doi: 10.1038/srep22208.
Three important physical properties which may affect the performance of glycoconjugate vaccines against serious disease are molar mass (molecular weight), heterogeneity (polydispersity), and conformational flexibility in solution. The dilute solution behaviour of native and activated capsular polyribosylribitol (PRP) polysaccharides extracted from Haemophilus influenzae type b (Hib), and the corresponding glycoconjugate made by conjugating this with the tetanus toxoid (TT) protein have been characterized and compared using a combination of sedimentation equilibrium and sedimentation velocity in the analytical ultracentrifuge with viscometry. The weight average molar mass of the activated material was considerably reduced (Mw ~ 0.24 × 10(6) g.mol(-1)) compared to the native (Mw ~ 1.2 × 10(6) g.mol(-1)). Conjugation with the TT protein yielded large polydisperse structures (of Mw ~ 7.4 × 10(6) g.mol(-1)), but which retained the high degree of flexibility of the native and activated polysaccharide, with frictional ratio, intrinsic viscosity, sedimentation conformation zoning behaviour and persistence length all commensurate with highly flexible coil behaviour and unlike the previously characterised tetanus toxoid protein (slightly extended and hydrodynamically compact structure with an aspect ratio of ~3). This non-protein like behaviour clearly indicates that it is the carbohydrate component which mainly influences the physical behaviour of the glycoconjugate in solution.
可能影响抗严重疾病糖缀合物疫苗性能的三个重要物理性质是摩尔质量（分子量）、异质性（多分散性）和溶液中的构象灵活性。使用分析超速离心机中的沉降平衡和沉降速度结合粘度测定法，对从b型流感嗜血杆菌（Hib）中提取的天然和活化的荚膜多聚核糖醇（PRP）多糖，以及将其与破伤风类毒素（TT）蛋白偶联制成的相应糖缀合物的稀溶液行为进行了表征和比较。与天然物质（Mw ~ 1.2 × 10(6) g.mol(-1)）相比，活化物质的重均摩尔质量大幅降低（Mw ~ 0.24 × 10(6) g.mol(-1)）。与TT蛋白偶联产生了大的多分散结构（Mw ~ 7.4 × 10(6) g.mol(-1)），但保留了天然和活化多糖的高度灵活性，摩擦比、特性粘度、沉降构象分区行为和持久长度都与高度灵活的卷曲行为一致，与先前表征的破伤风类毒素蛋白不同（略微伸展且流体动力学紧密的结构，长宽比约为3）。这种非蛋白质样行为清楚地表明，主要影响糖缀合物在溶液中物理行为的是碳水化合物成分。
