Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou, Fundação Oswaldo Cruz - FIOCRUZ-Minas, Belo Horizonte, Brazil.
Laboratório de Virologia Básica e Aplicada, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Front Immunol. 2019 Jun 21;10:1211. doi: 10.3389/fimmu.2019.01211. eCollection 2019.
The present study aims to determine whether 17DD-YF-specific humoral and cellular immunological memory is maintained 8-years after primary vaccination with subdoses (10,447IU;3,013IU;587IU;158IU;31IU). For this purpose, this follow-up study was carried out in a subset of volunteers ( = 98) originally enrolled in the dose-response study in 2009 and 46 non-vaccinated controls. Our results demonstrated that vaccinees, who had seroconverted following primary vaccination and had not been revaccinated, present similar neutralizing antibodies levels and YF-specific cellular memory, particularly CMCD4 and EMCD8 as compared to the reference full dose (27,476IU). Although, PRNT seropositivity rates were similar across subgroups (94, 82, 83, 94, 80, and 91%, correspondingly), only doses above 587IU elicited similar iterative proportion of seropositivity rates, calculated as a progressive decrease on seropositivity rates along time (89, 80, 80, and 91%, respectively) as compared to 158IU and 31IU (68 and 46%, respectively). Noteworthy were the strong positive correlations ("EMCD4,EMCD8" and "TNFCD8,IFNCD8") observed in most subdoses, except for 31IU. Major similarities underscored the preserved antibody titers and the outstanding levels of EMCD8, relevant correlates of protection for YF-specific immunity. These findings provide evidences to support the regular use of dose sparing strategy for YF vaccine in adults.
本研究旨在确定在亚剂量（10447IU；3013IU；587IU；158IU；31IU）初次接种后 8 年，17DD-YF 特异性体液和细胞免疫记忆是否得到维持。为此，在最初于 2009 年参加剂量反应研究的志愿者亚组（=98）中进行了这项随访研究，并纳入 46 名未接种疫苗的对照者。我们的结果表明，在初次接种后发生血清转化且未再次接种的疫苗接种者，与参考全剂量（27476IU）相比，具有相似的中和抗体水平和 YF 特异性细胞记忆，特别是 CMCD4 和 EMCD8。尽管各亚组的 PRNT 血清阳性率相似（分别为 94%、82%、83%、94%、80%和 91%），但只有高于 587IU 的剂量才能产生相似的迭代血清阳性率，这一比例是随着时间的推移血清阳性率逐渐降低（分别为 89%、80%、80%和 91%），而低于 158IU 和 31IU 的血清阳性率（分别为 68%和 46%）。值得注意的是，除了 31IU 之外，大多数亚剂量观察到强烈的正相关（“EMCD4，EMCD8”和“TNFCD8，IFNCD8”）。这些发现为成人 YF 疫苗采用剂量节约策略提供了证据支持。
