PNEUMOCOCCAL POLYSACCHARIDE PROTEIN CONJUGATE VACCINES

最近获得许可的肺炎球菌结合疫苗包含7种不同类型（4、6B、9V、14、18C、19F和23F）与CRM197蛋白结合。比率浊度法的免疫化学测定法被用于评估多价肺炎球菌疫苗中单个PS的含量。浊度法测量散射光通过沉淀反应形成的抗原-抗体复合物时的强度。用浊度法定量PS含量时，需要确定PS和抗体的最佳浓度。因此，本研究的目的是确定定量测定多价PS蛋白结合疫苗中单个PS的最佳条件。用胰蛋白酶处理多价结合疫苗以消化载体蛋白，从而将ps释放到溶液中。作为参考，单价结合疫苗，10 ug/ml，用胰蛋白酶处理，并将释放的ps稀释到不同浓度（0.5 ~ 10 ug/ml）。使用的抗血清是针对每种肺炎球菌的型特异性超免疫兔血清。

The recently licensed pneumococcal conjugate vaccine contains 7 different types (4, 6B, 9V, 14, 18C, 19F, and 23F) conjugated to CRM197 protein. The immunochemical assay by rate nephelometry is being used for evaluation of individual PS content in polyvalent pneumococcal vaccines. Nephelometry measures the intensity of scattered light as it is passed through the antigen-antibody complex formed by the precipitin reaction. For quantitation of PS content by nephelometry, the optimum concentrations for PSs and antibodies need to be determined. The objective of the present study was therefore to determine the optimum conditions for quantitative determination of individual PS in a polyvalent PS-protein conjugate vaccine. A multivalent conjugate vaccine was treated with trypsin to digest the carrier protein, thus releasing PSs into solution. For reference, monovalent conjugate vaccines, 10 ug/ml, were treated with trypsin and the released PSs diluted to different concentrations.(0.5 to 10 ug/ml) The antisera used were type specific hyperimmune rabbit sera against each pneumococcal type. Standard curves for types 4, 6B, 9V, 14, 18C, 19F, and 23F PSs were proportional to the increase of PS concentration in the range of 0.5 to 10 ug/ml. An excess or high PS concentration resulted in inhibition of the precipitin reaction and a reduction in the Ag-Ab complexes and thereby a decreased scattering rate. The optimum concentration for these 7 PS types, displaying linearity when used with their respective antisera, was found to be 1-5 ug/ml. Rate nephelometry is simple in operation, utilizes small quantities of antigen and antibody, and yields reproducible and accurate data for the quantitative analyses of individual PSs in polyvalent vaccines. However, it requires the reference standards for PS antigens and specific high titered antisera. Substances and conditions that may interfere with the nephelometric immunoassay system are being examined.