Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Buenos Aires, Argentina.
Fundación Huésped, Buenos Aires, Argentina.
Front Immunol. 2018 Oct 23;9:2443. doi: 10.3389/fimmu.2018.02443. eCollection 2018.
Since anti-HIV treatment cannot cure the infection, many strategies have been proposed to eradicate the viral reservoir, which still remains as a major challenge. The success of some of these strategies will rely on the ability of HIV-specific CD8 T-cells (CD8TC) to clear reactivated infected cells. Here, we aimed to investigate the phenotype and function of expanded CD8TC obtained from HIV subjects on combination antiretroviral therapy (cART), either initiated earlier (median = 3 months postinfection, ET: Early treatment) or later (median = 20 months postinfection, DT: Delayed treatment) after infection. Peripheral blood mononuclear cells from 12 DT and 13 ET subjects were obtained and stimulated with Nef and Gag peptide pools plus IL-2 for 14 days. ELISPOT was performed pre- and post-expansion. CD8TC memory/effector phenotype, PD-1 expression, polyfunctionality (CD107a/b, IFN-γ, IL-2, CCL4 (MIP-1β), and/or TNF-α production) and antiviral activity were evaluated post-expansion. Magnitude of ELISPOT responses increased after expansion by 10 times, in both groups. Expanded cells were highly polyfunctional, regardless of time of cART initiation. The memory/effector phenotype distribution was sharply skewed toward an effector phenotype after expansion in both groups although ET subjects showed significantly higher proportions of stem-cell and central memory CD8TCs. PD-1 expression was clustered in HIV-specific effector memory CD8TCs, subset that also showed the highest proportion of cytokine-producing cells. Moreover, PD-1 expression directly correlated with CD8TC functionality. Expanded CD8TCs from DT and ET subjects were highly capable of mediating antiviral activity, measured by two different assays. Antiviral function directly correlated with the proportion of fully differentiated effector cells (viral inhibition assay) as well as with CD8TC polyfunctionality and PD-1 expression (VITAL assay). In sum, we show that, despite being dampened in subjects on cART, the HIV-specific CD8TC response could be selectively stimulated and expanded , presenting a high proportion of cells able to carry-out multiple effector functions. Timing of cART initiation had an impact on the memory/effector differentiation phenotype, most likely reflecting how different periods of antigen persistence affected immune function. Overall, these results have important implications for the design and evaluation of strategies aimed at modulating CD8TCs to achieve the HIV functional cure.
由于抗 HIV 治疗无法治愈感染，因此提出了许多消除病毒储存库的策略，这仍然是一个主要挑战。这些策略的成功将取决于 HIV 特异性 CD8 T 细胞（CD8TC）清除再激活感染细胞的能力。在这里，我们旨在研究接受联合抗逆转录病毒治疗（cART）的 HIV 感染者中，从感染后较早（中位= 3 个月，ET：早期治疗）或较晚（中位= 20 个月，DT：延迟治疗）开始治疗的扩增 CD8TC 的表型和功能。从 12 名 DT 和 13 名 ET 受试者中获得外周血单核细胞，并在 IL-2 存在下用 Nef 和 Gag 肽池刺激 14 天。在扩增前和扩增后进行 ELISPOT。评估 CD8TC 记忆/效应器表型、PD-1 表达、多功能性（CD107a/b、IFN-γ、IL-2、CCL4（MIP-1β）和/或 TNF-α 的产生）和抗病毒活性。在两组中，ELISPOT 反应在扩增后增加了 10 倍。无论 cART 开始时间如何，扩增后的细胞都具有高度的多功能性。尽管 ET 受试者的干细胞和中央记忆 CD8TC 比例明显更高，但两组的记忆/效应器表型分布都明显偏向于效应器表型。PD-1 表达在两组中的 HIV 特异性效应记忆 CD8TC 中聚集，该亚群中产生细胞因子的细胞比例也最高。此外，PD-1 表达与 CD8TC 功能直接相关。来自 DT 和 ET 受试者的扩增 CD8TC 能够通过两种不同的测定法介导抗病毒活性。抗病毒功能与完全分化的效应细胞比例（病毒抑制测定法）以及 CD8TC 的多功能性和 PD-1 表达直接相关（VITAL 测定法）。总之，我们表明，尽管在接受 cART 的受试者中受到抑制，但 HIV 特异性 CD8TC 反应可以被选择性地刺激和扩增，表现出能够进行多种效应功能的高比例细胞。cART 开始时间对记忆/效应分化表型有影响，这很可能反映了不同时期的抗原持续存在如何影响免疫功能。总的来说，这些结果对设计和评估旨在调节 CD8TC 以实现 HIV 功能性治愈的策略具有重要意义。
