A single 17D Yellow Fever vaccination provides lifelong immunity; characterization of Yellow-Fever-specific neutralizing antibody and T-cell responses after vaccination

Introduction: Prompted by recent amendments of Yellow Fever (YF) vaccination guidelines from boost to single vaccination strategy and the paucity of clinical data to support this adjustment, we used the profile of the YF-specific CD8+ T-cell subset profiles after primary vaccination and neutralizing antibodies as a proxy for potentially longer lasting immunity. Methods and Findings: PBMCs and serum were collected in six individuals on days 0, 3, 5, 12, 28 and 180, and in 99 individuals >10 years after YF-vaccination. Phenotypic characteristics of YF- tetramer+ CD8+ T-cells were determined using class I tetramers. Antibody responses were measured using a standardized plaque reduction neutralization test (PRNT). Also, characteristics of YF-tetramer positive CD8+ T-cells were compared between individuals who had received a primary- and a booster vaccination. YF-tetramer+ CD8+ T-cells were detectable on day 12 (median tetramer+ cells as percentage of CD8+ T-cells 0.2%, range 0.07–3.1%). ...

引言：受黄热病（Yellow Fever, YF）疫苗接种指南从加强针方案调整为单剂接种方案的最新修订，以及缺乏支持该调整的临床数据所推动，我们以初次接种黄热病疫苗后黄热病毒特异性CD8+ T细胞亚群特征及中和抗体作为潜在持久免疫力的替代评估指标。
方法与结果：我们收集了6名受试者在接种后第0、3、5、12、28和180天的外周血单个核细胞（Peripheral Blood Mononuclear Cells, PBMCs）与血清，同时收集了99名黄热病疫苗接种后超过10年的受试者的样本。使用Ⅰ类四聚体（class I tetramers）检测黄热病毒四聚体阳性CD8+ T细胞的表型特征；采用标准化空斑减少中和试验（plaque reduction neutralization test, PRNT）检测抗体应答水平。此外，我们对比了初次接种与加强接种黄热病疫苗受试者的黄热病毒四聚体阳性CD8+ T细胞特征。黄热病毒四聚体阳性CD8+ T细胞可在接种后第12天被检测到（四聚体阳性细胞占CD8+ T细胞的中位数为0.2%，范围0.07%~3.1%）。