Specific killing of latently HIV-1-infected cells after provirus reactivation

描述(申请人提供)：艾滋病毒-1大流行已经夺走了2000多万人的生命，目前全世界有3860万人感染，并将继续成为一个重要的 全球健康问题，因为没有疫苗可用。目前，对HIV-1感染唯一有效的治疗方法是HAART(高效抗逆转录病毒疗法)，它已大大降低了与HIV-1相关的发病率和死亡率。然而，HAART未能在体内消除病毒，主要是因为长期存在携带有复制能力的前病毒的潜伏感染细胞。清除这些受感染细胞的努力主要集中在重新激活前病毒。据推测，这些被感染的细胞在病毒基因表达重新激活后，会被病毒细胞病变效应(CPE)或宿主免疫反应或两者兼而有之地杀死。几种刺激剂包括IL-7、丙戊酸(VPA)、琥珀酰异羟肟酸(SAHA)和前列腺素(Prostratin)已被探索用来强制激活潜伏感染的静息CD4T细胞中的前病毒，这些细胞构成了体内HIV-1的主要储存库。然而，接受HAART的患者使用IL-7或VPA治疗未能减少HIV-1潜伏期，这表明仅靠这些药物不足以诱导杀死潜伏感染的细胞。我们建议开发 通过将前病毒刺激物与一种能够使HIV-1感染期间患者自然产生的抗HIV-1免疫特异地杀死的试剂相结合的“激活-杀死”方法 潜伏感染的细胞在前病毒重新激活后。研究表明，HIV-1感染细胞和病毒粒子都使用其表面补体激活调节剂(RCA)来抵抗抗体依赖的补体介导的裂解(ADCML)，这解释了为什么在几乎所有感染者中强烈而持续的抗HIV-1包膜抗体(Ab)反应都无法控制HIV-1感染。我们和其他人已经报道，阻断人CD59(HCD59)，RCA的关键成员，使HIV-1感染的细胞和病毒粒子对ADCML敏感。因此，我们假设，在SAHA、Prostratin或两者中添加hCD59抑制剂将使HIV-1感染者中自然存在的抗HIV-1环境抗体能够在前病毒重新激活后触发潜伏感染的T细胞的ADCML。前病毒刺激剂将激活前病毒，在潜伏感染细胞的表面表达病毒蛋白，如果抑制hCD59，这些蛋白将被ADCML杀死。我们将使用人类T细胞系ACH2，一个很好地描述HIV-1潜伏期的模型，来开发这样的方法(目标1，R21阶段)。我们将验证该方法是否能够在体外触发潜伏感染HIV-1的原代CD4T细胞的ADCML(AIM 2，R33阶段)。然后，我们将确定这种方法是否可以允许感染患者血清中自然存在的抗HIV-1抗体触发他们自己的潜伏感染的静止CD4T细胞的自体ADCML(目标3，R33阶段)。我们的项目具有创新性和重要意义，因为我们的目标是开发一种新的方法来清除接受HAART的患者体内持久的HIV-1储存库。这种方法可能同时针对各种潜伏感染的细胞和残留的病毒血症，潜在地导致更广泛的影响和改善对各种持续的HIV-1储存库的疗效。

DESCRIPTION (provided by applicant): The HIV-1 pandemic has claimed over 20 million lives, with 38.6 million people worldwide currently infected, and will continue to be a significant global health problem as there is no vaccine available. Currently, the only effective treatment available to HIV-1 infection is HAART (highly active antiretroviral therapy), which has led to a profound reduction in HIV-1-related morbidity and mortality. However, HAART fails to eliminate the virus in vivo, mainly due to the persistent existence of long-lived latently-infected cells harboring replication-competent proviruses. Efforts to purge these infected cells have focused on reactivation of the proviruses. It is presumed that these infected cells will be killed after reactivation of virus gene expression by viral cytopathic effects (CPEs), host immune responses or both. Several stimulants including IL-7, valproic acid (VPA), suberoylanilide hydroxamic acid (SAHA) and prostratin have been explored to force activation of proviruses in latently-infected resting CD4+ T cells that constitute the major reservoir of HIV-1 in vivo. However, treatment with IL-7 or VPA in patients on HAART has failed to reduce HIV-1 latency, suggesting that these agents alone are not sufficient to induce killing of latently-infected cells. We propose to develop an "activation-killing" approach by combining provirus stimulants with an agent that is able to allow anti-HIV-1 immunity naturally mounted in patients during HIV-1 infection to specifically kill latently-infected cells after provirus reactivation. Studies have shown that both HIV-1-infected cells and virions use their surface regulators of complement activation (RCA) to resist antibody- dependent complement-mediated lysis (ADCML), which explains why vigorous and sustained anti-HIV-1 envelope (Env) antibody (Ab) responses in almost all infected individuals fail to control HIV-1 infection. We and others have reported that blocking human CD59 (hCD59), a key member of RCA, renders both HIV-1-infected cells and virions sensitive to ADCML. We therefore hypothesize that addition of an hCD59 inhibitor to SAHA, prostratin or both will enable anti-HIV-1 Env Abs naturally present in HIV-1-infected individuals to trigger ADCML of latently-infected T cells after provirus reactivation. The provirus stimulants will activate proviruses to express viral proteins on the surface of latently-infected cells that will be killed by ADCML if hCD59 is inhibited. We will use the human T cell line ACH2, a well-characterized model of HIV-1-latency, to develop such an approach (Aim 1, R21 Phase). We will verify whether the approach is able to trigger ADCML of the primary CD4+ T cells latently infected with HIV-1 in vitro (Aim 2, R33 Phase). We will then determine if this approach can allow anti-HIV-1 Abs naturally present in the sera of infected patients to trigger autologous ADCML of their own latently-infected resting CD4+ T cells (Aim 3, R33 Phase). Our project is innovative and significant because we aim to develop a novel approach for purging the persistent reservoir of HIV-1 in patients on HAART. This approach may simultaneously target various latently infected cells and residual viremia, potentially leading to a broader impact and improved efficacy against the various persistent HIV-1 reservoirs.