Control of HIV-1 replication in vitro by vaccine-induced human CD8(+) T cells through conserved subdominant Pol epitopes.
Control of HIV-1 replication in vitro by vaccine-induced human CD8(+) T cells through conserved subdominant Pol epitopes.
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DOI：
10.1016/j.vaccine.2015.12.021
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发表时间：
2016-02-24
期刊：
影响因子：
5.5
通讯作者：
Hanke T
中科院分区：
文献类型：
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作者：
Ahmed T;Borthwick NJ;Gilmour J;Hayes P;Dorrell L;Hanke T
CD8+T细胞的特异性对于早期控制HIV-1的建立/传播和再激活至关重要。为了应对HIV-1的变异性和逃逸，我们设计了疫苗免疫原HIVconv，它由14个高度保守的区域组成，主要是Gag和Pol蛋白。当在HIV-CORE 002试验中给HIV-1阴性的人类志愿者注射HIVconv疫苗时，HIVconv疫苗诱导CD8+效应T细胞，从而抑制多达8个HIV-1分离株在自体CD4+细胞中的复制。这种抑制与GAG和POL多肽库反应中干扰素-γ的产生有关，但缺乏抑制特异性的直接证据。在这里，我们的目的是通过识别这些效应器抑制HIV-1复制的表位来确定。在23个疫苗接受者中，来自3种最广泛的HIV-1抑制剂的CD8+T细胞通过GAG或Pol肽再刺激在培养中扩增，并用HIV-1 B和A分离株进行病毒抑制试验(VIA)。首先使用GAG或Pol保守区的多肽库扩增冷冻的PBMC，并在HIV-1感染细胞上用VIA或由单个多肽测试其效应功能。然后，通过在HIV-1感染细胞上测试单肽扩展效应器来确认负责抑制HIV-1复制的单肽特异性。我们正式证明了疫苗诱导的抑制性人CD8+T细胞识别Pol和Gag蛋白的保守表位。我们定义了7个最小表位，其中3个是新的，推测是自然亚显性的。效应器是功能少的，产生几种细胞因子和趋化因子，并杀伤多肽脉冲的靶细胞。这些结果表明，除了广泛使用的GAG用于T细胞疫苗设计外，还可以使用POL的功能保守区。开发这些效应器的志愿者比例和它们在循环PBMC中的频率是两个独立的问题，如果需要的话，可以通过更有效的载体和方案传递保守的免疫原来解决。
The specificity of CD8+ T cells is critical for early control of founder/transmitted and reactivated HIV-1. To tackle HIV-1 variability and escape, we designed vaccine immunogen HIVconsv assembled from 14 highly conserved regions of mainly Gag and Pol proteins. When administered to HIV-1-negative human volunteers in trial HIV-CORE 002, HIVconsv vaccines elicited CD8+ effector T cells which inhibited replication of up to 8 HIV-1 isolates in autologous CD4+ cells. This inhibition correlated with interferon-γ production in response to Gag and Pol peptide pools, but direct evidence of the inhibitory specificity was missing. Here, we aimed to define through recognition of which epitopes these effectors inhibit HIV-1 replication. CD8+ T-cells from the 3 broadest HIV-1 inhibitors out of 23 vaccine recipients were expanded in culture by Gag or Pol peptide restimulation and tested in viral inhibition assay (VIA) using HIV-1 clade B and A isolates. Frozen PBMCs were expanded first using peptide pools from Gag or Pol conserved regions and tested on HIV-1-infected cells in VIA or by individual peptides for their effector functions. Single peptide specificities responsible for inhibition of HIV-1 replication were then confirmed by single-peptide expanded effectors tested on HIV-1-infected cells. We formally demonstrated that the vaccine-elicited inhibitory human CD8+ T cells recognized conserved epitopes of both Pol and Gag proteins. We defined 7 minimum epitopes, of which 3 were novel, presumably naturally subdominant. The effectors were oligofunctional producing several cytokines and chemokines and killing peptide-pulsed target cells. These results implicate the use of functionally conserved regions of Pol in addition to the widely used Gag for T-cell vaccine design. Proportion of volunteers developing these effectors and their frequency in circulating PBMC are separate issues, which can be addressed, if needed, by more efficient vector and regimen delivery of conserved immunogens.