Laboratório de Desenvolvimento de Processos, Centro de Biotecnologia, Instituto Butantan, Brazil.
Laboratório de Desenvolvimento de Processos, Centro de Biotecnologia, Instituto Butantan, Brazil.
Carbohydr Polym. 2015 Feb 13;116:167-72. doi: 10.1016/j.carbpol.2014.04.004. Epub 2014 Apr 13.
Haemophilus influenzae type b (Hib) is a human pathogen that causes severe infections such as pneumonia, sepsis and meningitis. Vaccines for Hib infections are based on its capsular polysaccharide conjugated to a protein. This conjugated Hib antigen is included as one of the components of polyvalent vaccines and accounts for more than 50% of the total cost of the formulations. The instability of the polysaccharide is responsible for the high cost of the vaccine. In this study, the factors affecting the spontaneous degradation of the polysaccharide from Hib were evaluated based on the decrease in its molecular mass, as measured by size-exclusion chromatography. Temperature and pH were found to be the most significant variables, and the results showed that the conditions of bacterial cell growth (37 °C and pH 7.5) are favourable for depolymerization. An increase in the concentration of sodium ions up to 200 mM intensified the effect of pH, allowing higher rates of depolymerization at lower pH values, whereas the presence of magnesium ions showed no effects.
乙型流感嗜血杆菌（Hib）是一种能引起肺炎、败血症和脑膜炎等严重感染的人类病原体。针对 Hib 感染的疫苗是基于其荚膜多糖与蛋白质的结合。这种结合型 Hib 抗原是多价疫苗的成分之一，占配方总成本的 50%以上。多糖的不稳定性是导致疫苗高成本的原因。在这项研究中，根据大小排阻色谱法测量的分子量下降，评估了影响 Hib 多糖自发降解的因素。发现温度和 pH 是最重要的变量，结果表明细菌细胞生长的条件（37°C 和 pH 7.5）有利于解聚。钠离子浓度增加到 200 mM 会增强 pH 的影响，允许在较低的 pH 值下实现更高的解聚速率，而镁离子的存在则没有影响。
