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

描述（由申请人提供）：HIV-1大流行已经夺去了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大的流行病。 这是一个全球性的健康问题，因为没有疫苗。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），它大大降低了HIV-1相关的发病率和死亡率。然而，HAART未能消除体内病毒，主要是由于长期存在的潜伏感染的细胞窝藏复制能力的前病毒。清除这些受感染细胞的努力集中在重新激活前病毒上。据推测，这些感染的细胞将在病毒基因表达被病毒致细胞病变效应（CPE）、宿主免疫应答或两者重新激活后被杀死。已经探索了包括IL-7、丙戊酸（VPA）、辛二酰苯胺异羟肟酸（SAHA）和prostratin在内的几种刺激剂，以迫使构成体内HIV-1的主要储库的潜伏感染的静息CD 4 + T细胞中的前病毒活化。然而，在HAART患者中用IL-7或VPA治疗未能减少HIV-1潜伏期，这表明单独使用这些药物不足以诱导杀死潜伏感染的细胞。我们建议发展 通过将前病毒刺激剂与能够在HIV-1感染期间使抗HIV-1免疫在患者中自然建立的试剂组合的“活化-杀伤”方法， 前病毒再激活后潜伏感染的细胞。研究表明，HIV-1感染的细胞和病毒体都使用其补体激活（RCA）的表面调节因子来抵抗抗体依赖性补体介导的裂解（ADCML），这解释了为什么几乎所有感染个体中强烈和持续的抗HIV-1包膜（Env）抗体（Ab）应答都无法控制HIV-1感染。我们和其他人已经报道，阻断RCA的关键成员人CD 59（hCD 59），使HIV-1感染的细胞和病毒粒子对ADCML敏感。因此，我们假设向SAHA、prostratin或两者中添加hCD 59抑制剂将使天然存在于HIV-1感染个体中的抗HIV-1 Env Ab能够在原病毒再活化后触发潜伏感染T细胞的ADCML。前病毒刺激物将激活前病毒以在潜伏感染细胞的表面上表达病毒蛋白，如果hCD 59被抑制，则所述潜伏感染细胞将被ADCML杀死。我们将使用人类T细胞系ACH 2（一种充分表征的HIV-1潜伏期模型）来开发这种方法（目标1，R21阶段）。我们将验证该方法是否能够在体外触发HIV-1潜伏感染的原代CD 4 + T细胞的ADCML（目标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天然存在的抗HIV-1抗体触发其自身潜伏感染的静息CD 4 + T细胞的自体ADCML（Aim 3，R33阶段）。我们的项目是创新和重要的，因为我们的目标是开发一种新的方法来清除HAART患者中持续存在的HIV-1。这种方法可以同时靶向各种潜伏感染的细胞和残留的病毒血症，可能导致更广泛的影响和改善对各种持续的HIV-1储库的疗效。

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.