Development of a Fourfold Multiplexed Opsonophagocytosis Assay for Pneumococcal Antibodies against Additional Serotypes and Discovery of Serological Subtypes in Streptococcus pneumoniae Serotype 20
Development of a Fourfold Multiplexed Opsonophagocytosis Assay for Pneumococcal Antibodies against Additional Serotypes and Discovery of Serological Subtypes in Streptococcus pneumoniae Serotype 20
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DOI：
10.1128/cvi.00086-12
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发表时间：
2012-06-01
影响因子：
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通讯作者：
Nahm, Moon H.
中科院分区：
文献类型：
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作者：
Burton, Robert L.;Nahm, Moon H.
调理吞噬细胞杀伤试验（OPA）是肺炎链球菌疫苗研究中重要的体外保护性替代标志物。我们之前已经报道了Prevnar 13中13种血清型的4倍多重OPA（MOPA）的开发。由于正在开发效价增加的新偶联疫苗，我们开发了另外13种血清型的4倍MOPA：血清型6C和6D，加上Pneumovax中含有的11种血清型，但Prevnar 13中不含。在多批幼兔补体中观察到三种血清型（10A、15 B和33 F）的高水平非特异性杀伤（NSK）。NSK可以通过用包封的以及未包封的肺炎球菌菌株预吸附补体来降低。MOPA结果与单一血清型OPA结果相比，除血清3型外，所有血清型的结果都很好。对于血清型3，从MOPA格式获得的结果相似，比单血清型格式高40%。用5份血清测定了MOPA的批间精密度，变异系数一般为80 mg/L。这表明血清型20菌株之间存在血清学异质性。
Opsonophagocytic killing assays (OPAs) are important in vitro surrogate markers of protection in vaccine studies of Streptococcus pneumoniae. We have previously reported the development of a 4-fold multiplexed OPA (MOPA) for the 13 serotypes in Prevnar 13. Because new conjugate vaccines with increased valence are being developed, we developed 4-fold MOPAs for an additional 13 serotypes: serotypes 6C and 6D, plus the 11 serotypes contained in Pneumovax but not in Prevnar 13. A high level of nonspecific killing (NSK) was observed for three serotypes (10A, 15B, and 33F) in multiple batches of baby rabbit complement. The NSK could be reduced by preadsorbing the complement with encapsulated, as well as unencapsulated, pneumococcal strains. The MOPA results compared well with the results of single-serotype OPA for all serotypes except for serotype 3. For serotype 3, the results obtained from the MOPA format were similar to 40% higher than those of the single-serotype format. Interassay precision of MOPA was determined with 5 serum samples, and the coefficient of variation was generally 80 mg/liter) PS concentration. This suggests the presence of serologic heterogeneity among serotype 20 strains.