There is growing interest in understanding antibody (Ab) function beyond neutralization. The non-structural protein 1 (NS1) of Zika virus (ZIKV) is an attractive candidate for an effective vaccine as Abs against NS1, unlike the envelope or premembrane, do not carry the risk of mediating antibody-dependent enhancement. Our aim was to evaluate whether ZIKV NS1 Abs elicited following natural infection in humans can mediate antibody-dependent cellular cytotoxicity (ADCC). We evaluated the isotype specificity of ZIKV-specific Abs in immune sera and supernatants from stimulated immune PBMC and found that Abs against ZIKV NS1 and virus-like particles were predominantly of the IgG1 isotype. Using a recently developed FluoroSpot assay, we found robust frequencies of NS1-specific Ab-secreting cells in PBMC of individuals who were naturally infected with ZIKV. We developed assays to measure both natural killer cell activation by flow cytometry and target cell lysis of ZIKV NS1-expressing cells using an image cytometry assay in the presence of ZIKV NS1 Abs. Our data indicate efficient opsonization of ZIKV NS1-expressing CEM-NK^R cell lines using ZIKV-immune but not ZIKV-naïve sera, a prerequisite of ADCC. Furthermore, sera from immune donors were able to induce both NK cell degranulation and lysis of ZIKV NS1 CEM-NK^R cells in vitro. Our data suggest that ADCC is a possible mechanism for ZIKV NS1 Abs to eliminate virally infected target cells.

中文翻译：

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针对人类寨卡病毒的非结构蛋白 1 特异性抗体介导抗体依赖性细胞毒性

人们对了解除中和之外的抗体 (Ab) 功能越来越感兴趣。寨卡病毒 (ZIKV) 的非结构蛋白 1 (NS1) 是有效疫苗的有吸引力的候选者，因为针对 NS1 的抗体与包膜或前膜不同，不具有介导抗体依赖性增强的风险。我们的目的是评估在人类自然感染后引发的 ZIKV NS1 Abs 是否可以介导抗体依赖性细胞毒性 (ADCC)。我们评估了免疫血清和受激免疫 PBMC 上清液中 ZIKV 特异性抗体的同种型特异性，发现针对 ZIKV NS1 和病毒样颗粒的抗体主要是 IgG1 同种型。使用最近开发的 FluoroSpot 检测，我们发现自然感染 ZIKV 的个体的 PBMC 中 NS1 特异性 Ab 分泌细胞的频率很高。我们开发了通过流式细胞术测量自然杀伤细胞活化和在 ZIKV NS1 Ab 存在的情况下使用图像细胞术检测 ZIKV NS1 表达细胞的靶细胞裂解的检测方法。我们的数据表明 ZIKV NS1 表达 CEM-NK 的有效调理使用 ZIKV 免疫而非 ZIKV 幼稚血清的^R细胞系，这是 ADCC 的先决条件。此外，免疫供体的血清能够在体外诱导 NK 细胞脱颗粒和 ZIKV NS1 CEM-NK ^R细胞裂解。我们的数据表明 ADCC 是 ZIKV NS1 Ab 消除病毒感染靶细胞的可能机制。