Penkert Rhiannon R, Chandramouli Sumana, Dormitzer Philip R, Settembre Ethan C, Sealy Robert E, Wong Susan, Young Neal S, Sun Yilun, Tang Li, Cotton Alyssa, Dowdy Jola, Hayden Randall T, Hankins Jane S, Hurwitz Julia L
Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
Novartis Vaccines and Diagnostics, Cambridge, MA 02139, USA.
Vaccines (Basel). 2021 Aug 4;9(8):860. doi: 10.3390/vaccines9080860.
Children with sickle cell disease (SCD) suffer life-threatening transient aplastic crisis (TAC) when infected with parvovirus B19. In utero, infection of healthy fetuses may result in anemia, hydrops, and death. Unfortunately, although promising vaccine candidates exist, no product has yet been licensed. One barrier to vaccine development has been the lack of a cost-effective, standardized parvovirus B19 neutralization assay. To fill this void, we evaluated the unique region of VP1 (VP1u), which contains prominent targets of neutralizing antibodies. We discovered an antigenic cross-reactivity between VP1 and VP2 that, at first, thwarted the development of a surrogate neutralization assay. We overcame the cross-reactivity by designing a mutated VP1u (VP1uAT) fragment. A new VP1uAT ELISA yielded results well correlated with neutralization (Spearman's correlation coefficient = 0.581; = 0.001), superior to results from a standard clinical diagnostic ELISA or an ELISA with virus-like particles. Virus-specific antibodies from children with TAC, measured by the VP1uAT and neutralization assays, but not other assays, gradually increased from days 0 to 120 post-hospitalization. We propose that this novel and technically simple VP1uAT ELISA might now serve as a surrogate for the neutralization assay to support rapid development of a parvovirus B19 vaccine.
患有镰状细胞病（SCD）的儿童感染细小病毒B19时会遭遇危及生命的短暂性再生障碍危象（TAC）。在子宫内，健康胎儿感染可能会导致贫血、水肿和死亡。不幸的是，尽管有很有前景的候选疫苗，但尚无产品获得许可。疫苗开发的一个障碍是缺乏一种经济高效、标准化的细小病毒B19中和试验。为填补这一空白，我们评估了VP1的独特区域（VP1u），该区域包含中和抗体的主要靶点。我们发现VP1和VP2之间存在抗原交叉反应，这起初阻碍了替代中和试验的开发。我们通过设计一个突变的VP1u（VP1uAT）片段克服了交叉反应。一种新的VP1uAT ELISA检测结果与中和结果高度相关（斯皮尔曼相关系数 = 0.581；P = 0.001），优于标准临床诊断ELISA或使用病毒样颗粒的ELISA检测结果。通过VP1uAT和中和试验而非其他试验检测，TAC患儿的病毒特异性抗体在住院后第0天至120天逐渐增加。我们建议，这种新颖且技术简单的VP1uAT ELISA现在可作为中和试验的替代方法，以支持细小病毒B19疫苗的快速开发。
