The Peter Doherty Institute for Infection and Immunity, The University of Melbourne and Royal Melbourne Hospital, Melbourne, Australia.
Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.
J Virol. 2018 Jun 13;92(13). doi: 10.1128/JVI.02225-17. Print 2018 Jul 1.
HIV infection requires lifelong antiretroviral therapy because of the persistence of latently infected CD4 T cells. The induction of virus expression from latently infected cells occurs following T cell receptor (TCR) activation, but not all latently infected cells respond to TCR stimulation. We compared two models of latently infected cells using an enhanced green fluorescent protein (EGFP) reporter virus to infect CCL19-treated resting CD4 (rCD4) T cells (preactivation latency) or activated CD4 T cells that returned to a resting state (postactivation latency). We isolated latently infected cells by sorting for EGFP-negative (EGFP) cells after infection. These cells were cultured with antivirals and stimulated with anti-CD3/anti-CD28, mitogens, and latency-reversing agents (LRAs) and cocultured with monocytes and anti-CD3. Spontaneous EGFP expression was more frequent in postactivation than in preactivation latency. Stimulation of latently infected cells with monocytes/anti-CD3 resulted in an increase in EGFP expression compared to that for unstimulated controls using the preactivation latency model but led to a reduction in EGFP expression in the postactivation latency model. The reduced EGFP expression was not associated with reductions in the levels of viral DNA or T cell proliferation but depended on direct contact between monocytes and T cells. Monocytes added to the postactivation latency model during the establishment of latency reduced spontaneous virus expression, suggesting that monocyte-T cell interactions at an early time point postinfection can maintain HIV latency. This direct comparison of pre- and postactivation latency suggests that effective strategies needed to reverse latency will depend on how latency is established. One strategy being evaluated to eliminate latently infected cells that persist in HIV-infected individuals on antiretroviral therapy (ART) is to activate HIV expression or production with the goal of inducing virus-mediated cytolysis or immune-mediated clearance of infected cells. The gold standard for the activation of latent virus is T cell receptor stimulation with anti-CD3/anti-CD28. However, this stimulus activates only a small proportion of latently infected cells. We show clear differences in the responses of latently infected cells to activating stimuli based on how latent infection is established, an observation that may potentially explain the persistence of noninduced intact proviruses in HIV-infected individuals on ART.
HIV 感染需要终身抗逆转录病毒治疗，因为潜伏感染的 CD4 T 细胞持续存在。潜伏感染细胞中的病毒表达是在 T 细胞受体（TCR）激活后发生的，但并非所有潜伏感染细胞都对 TCR 刺激有反应。我们使用增强型绿色荧光蛋白（EGFP）报告病毒比较了两种潜伏感染细胞模型，该病毒感染 CCL19 处理的静止 CD4（rCD4）T 细胞（预激活潜伏）或返回静止状态的激活 CD4 T 细胞（后激活潜伏）。我们通过感染后对 EGFP 阴性（EGFP）细胞进行分选来分离潜伏感染细胞。将这些细胞与抗病毒药物一起培养，并使用抗 CD3/抗 CD28、有丝分裂原和潜伏逆转剂（LRAs）进行刺激，并与单核细胞和抗 CD3 共培养。与预激活潜伏相比，后激活潜伏中的自发 EGFP 表达更为频繁。与预激活潜伏模型相比，用单核细胞/抗 CD3 刺激潜伏感染细胞会导致 EGFP 表达增加，但在后激活潜伏模型中会导致 EGFP 表达减少。减少的 EGFP 表达与病毒 DNA 水平或 T 细胞增殖的减少无关，但取决于单核细胞与 T 细胞之间的直接接触。在建立潜伏感染期间，将单核细胞添加到后激活潜伏模型中会减少自发病毒表达，这表明感染后早期单核细胞与 T 细胞之间的相互作用可以维持 HIV 潜伏。这种对前激活和后激活潜伏的直接比较表明，逆转潜伏所需的有效策略将取决于潜伏的建立方式。一种正在评估的消除在接受抗逆转录病毒治疗（ART）的 HIV 感染者中持续存在的潜伏感染细胞的策略是用 HIV 表达或产生来激活潜伏病毒，目的是诱导病毒介导的细胞溶解或免疫介导的清除感染细胞。潜伏病毒激活的金标准是用抗 CD3/抗 CD28 刺激 T 细胞受体。然而，这种刺激仅激活一小部分潜伏感染细胞。我们根据潜伏感染的建立方式，清楚地观察到潜伏感染细胞对激活刺激的反应存在差异，这一观察结果可能解释了在接受 ART 的 HIV 感染者中，非诱导完整前病毒持续存在的原因。
