White Andrew D, Sarfas Charlotte, Sibley Laura S, Gullick Jennie, Clark Simon, Rayner Emma, Gleeson Fergus, Català Martí, Nogueira Isabel, Cardona Pere-Joan, Vilaplana Cristina, Dennis Mike J, Williams Ann, Sharpe Sally A
Public Health England, National Infection Service, Porton Down, Salisbury SP4 0JG, UK.
The Churchill Hospital, Headington, Oxford OX3 7LE, UK.
Pharmaceutics. 2020 Apr 25;12(5):394. doi: 10.3390/pharmaceutics12050394.
Ten million cases of tuberculosis (TB) were reported in 2018 with a further 1.5 million deaths attributed to the disease. Improved vaccination strategies are urgently required to tackle the ongoing global TB epidemic. In the absence of a validated correlate of protection, highly characterised pre-clinical models are required to assess the protective efficacy of new vaccination strategies. In this study, we demonstrate the application of a rhesus macaque ultra-low dose (ULD) aerosol challenge model for the evaluation of TB vaccination strategies by directly comparing the immunogenicity and efficacy of intradermal (ID) and aerosol BCG vaccination delivered using a portable vibrating mesh nebulizer (VMN). Aerosol- and ID-delivered Bacille Calmette-Guérin (BCG) induced comparable frequencies of IFN-γ spot forming units (SFU) measured in peripheral blood mononuclear cells (PBMCs) by ELISpot, although the induction of IFN-γ SFU was significantly delayed following aerosol immunisation. This delayed response was also apparent in an array of secreted pro-inflammatory and chemokine markers, as well as in the frequency of antigen-specific cytokine producing CD4 and CD8 T-cells measured by multi-parameter flow cytometry. Interrogation of antigen-specific memory T-cell phenotypes revealed that vaccination-induced CD4 and CD8 T-cell populations primarily occupied the central memory (TCM) and transitional effector memory (TransEM) phenotype, and that the frequency of CD8 TCM and TransEM populations was significantly higher in aerosol BCG-vaccinated animals in the week prior to infection. The total and lung pathology measured following challenge was significantly lower in vaccinated animals relative to the unvaccinated control group and pathology measured in extra-pulmonary tissues was significantly reduced in aerosol BCG-vaccinated animals, relative to the ID-immunised group. Similarly, significantly fewer viable CFU were recovered from the extra-pulmonary tissues of aerosol BCG-vaccinated macaques relative to unvaccinated animals. In this study, a rhesus macaque ULD aerosol challenge model was applied as a refined and sensitive system for the evaluation of TB vaccine efficacy and to confirm that aerosol BCG vaccination delivered by portable VMN can confer a significant level of protection that is equivalent, and by some measures superior, to intradermal BCG vaccination.
2018年报告了1000万例结核病病例，另有150万人死于该疾病。迫切需要改进疫苗接种策略来应对持续的全球结核病流行。在缺乏经过验证的保护相关性指标的情况下，需要高度特征化的临床前模型来评估新疫苗接种策略的保护效果。在本研究中，我们通过直接比较使用便携式振动网雾化器（VMN）进行皮内（ID）和气溶胶卡介苗接种的免疫原性和效果，展示了恒河猴超低剂量（ULD）气溶胶攻击模型在评估结核病疫苗接种策略中的应用。气溶胶和ID接种的卡介苗（BCG）在通过ELISpot在外周血单核细胞（PBMCs）中测得的IFN-γ斑点形成单位（SFU）频率相当，尽管气溶胶免疫后IFN-γ SFU的诱导明显延迟。这种延迟反应在一系列分泌的促炎和趋化因子标志物中也很明显，以及在通过多参数流式细胞术测量的抗原特异性细胞因子产生CD4和CD8 T细胞频率中也很明显。对抗原特异性记忆T细胞表型的研究表明，疫苗接种诱导的CD4和CD8 T细胞群体主要占据中央记忆（TCM）和过渡效应记忆（TransEM）表型，并且在感染前一周，气溶胶卡介苗接种动物中CD8 TCM和TransEM群体的频率显著更高。与未接种疫苗的对照组相比，接种疫苗的动物在攻击后测量的总体和肺部病理学显著更低，并且与ID免疫组相比，气溶胶卡介苗接种动物在肺外组织中测量的病理学显著降低。同样，与未接种疫苗的动物相比，从气溶胶卡介苗接种猕猴的肺外组织中回收的活CFU显著更少。在本研究中，恒河猴ULD气溶胶攻击模型被用作评估结核病疫苗效果的精细且敏感的系统，并证实通过便携式VMN进行的气溶胶卡介苗接种可以提供显著水平的保护，这种保护等同于皮内卡介苗接种，并且在某些方面更优。
