AAV-mediated delivery of eCD4-Ig for prevention and treatment of perinatal HIV infection

项目总结 人类免疫缺陷病毒(HIV)的母婴传播仍导致数百人死亡 每年数以千计的新的儿科艾滋病毒感染，特别是在世界上资源匮乏的地区 获得产前/产后抗逆转录病毒疗法(ART)的机会有限。可悲的是，在没有抗逆转录病毒治疗的情况下，50%的艾滋病毒- 受感染的婴儿在2岁前死亡。因为单靠抗逆转录病毒治疗不足以结束发病率和死亡率。 与儿童的艾滋病毒/艾滋病有关，迫切需要制定切实的干预措施，以预防 并治疗儿童艾滋病毒感染。为此，该项目将评估基因治疗的潜力 有效和极其广泛的艾滋病毒抑制剂eCD4-Ig，用于预防和治疗围产期艾滋病毒感染。ECD4-Ig是一种 嵌合分子由CD4的外部结构域、免疫球蛋白Fc部分和辅助受体模拟肽组成。 ECD4-Ig对HIV-1、HIV-2和SIV具有无与伦比的广度和非常强大的效应活性。ECD4-Ig 基因将通过腺相关病毒(AAV)介导的基因传递给幼年恒河猴(RMS) 调职。AAV载体是安全的，可以转导分裂细胞和非分裂细胞。至关重要的是，AAV驱动 转基因在长寿命细胞中的表达，例如骨骼肌的转基因表达，可以持续数年，甚至数十年。 而AAV介导的eCD4-Ig传递已被证明能保护成人RMS免受致病病毒的攻击 携带高度分化的包膜蛋白的免疫缺陷病毒，这种方法从未在 婴儿。我们最近与Farzan实验室合作，表征了eCD4-Ig在 婴儿RMS出生时用AAV/eCD4-Ig治疗。与成年动物相比，AAV/eCD4-Ig处理的新生RMS 经历了显著更高的eCD4-Ig水平和更低水平的eCD4-Ig分子抗体水平。 请注意，这些抗药物抗体(ADA)对AAV介导的免疫球蛋白传递是非常有害的 因为它们可以清除循环中的分子，从而降低这种方法的有效性。低谷 在接受AAV/eCD4-Ig治疗的婴儿中观察到的ADAs水平与以前关于新生儿的报道一致 对AAV携带的转基因产品产生耐受性。鉴于AAV载体能够促进持续 一次性给药后的转基因表达，以及由转基因提供的独特机会之窗 新生儿期获得强劲的AAV驱动的eCD4-Ig在体内的表达，我们假设AAV介导 给婴儿注射eCD4-Ig可以预防和治疗产后艾滋病毒感染。在特定目标(SA)1中，我们将 描述AAV/eCD4-Ig在婴幼儿RMS中的安全性。在SA 2中，我们将确定新生儿分娩是否 AAV/eCD4-Ig可预防RMS患者SIVmac239的口服感染。在SA 3中，我们将评估AAV介导的 向感染SIV的婴儿RMS注射eCD4-Ig可以控制病毒复制，而不需要抗逆转录病毒治疗。如果成功，则 拟议的实验将为测试eCD4-Ig的AAV介导的基因治疗奠定临床前基础 在婴儿中作为预防和治疗围产期艾滋病毒感染的手段。

PROJECT SUMMARY Mother-to-child transmission of human immunodeficiency virus (HIV) still results in hundreds of thousands of new pediatric HIV infections every year, especially in resource-poor areas of the world where access to antenatal/postnatal antiretroviral therapy (ART) is limited. Sadly, in the absence of ART, >50% of HIV- infected infants die by 2 years of age. Since ART alone will not be sufficient to end the morbidity and mortality associated with HIV/AIDS in children, there is an urgent need for developing practical interventions to prevent and treat pediatric HIV infection. To that end, this project will evaluate the potential of gene therapy with the potent and extremely broad HIV inhibitor eCD4-Ig to prevent and treat perinatal HIV infection. eCD4-Ig is a chimeric molecule consisting of the outer domains of CD4, an IgG Fc portion, and a co-receptor mimetic peptide. eCD4-Ig has unmatched breadth and very potent effector activities against HIV-1, HIV-2, and SIV. The eCD4-Ig gene will be delivered to infant rhesus macaques (RMs) via adeno-associated virus (AAV)-mediated gene transfer. AAV vectors are safe and can transduce both dividing and non-dividing cells. Critically, AAV-driven transgene expression in long-lived cells, such as those of skeletal muscle, can last for years, possibly decades. While AAV-mediated delivery of eCD4-Ig has been shown to protect adult RMs against challenge with pathogenic immunodeficiency viruses bearing highly divergent Envelope proteins, this approach has never been tested in infants. We have recently partnered with the Farzan lab to characterize the kinetics of eCD4-Ig expression in infant RMs treated with AAV/eCD4-Ig at birth. Compared to adult animals, AAV/eCD4-Ig-treated newborn RMs experienced substantially higher levels of eCD4-Ig and lower levels of antibodies against the eCD4-Ig molecule. Note that these anti-drug antibodies (ADAs) are highly detrimental to AAV-mediated delivery of immunoglobulins because they can clear the molecules from circulation, thereby reducing the efficacy of this approach. The low levels of ADAs observed in the AAV/eCD4-Ig-treated infants is consistent with previous reports of neonates developing tolerance to AAV-delivered transgene products. Given the ability of AAV vectors to promote sustained transgene expression after a one-time administration, and the unique window of opportunity offered by the neonatal period to achieve robust AAV-driven expression of eCD4-Ig in vivo, we postulate that AAV-mediated delivery of eCD4-Ig to infants can prevent and treat postpartum HIV infection. In specific aim (SA) 1, we will characterize the safety profile of AAV/eCD4-Ig in infant RMs. In SA 2, we will determine if neonatal delivery of AAV/eCD4-Ig can prevent oral acquisition of SIVmac239 in RMs. In SA 3, we will assess if AAV-mediated delivery of eCD4-Ig to SIV-infected infant RMs can control viral replication without ART. If successful, the proposed experiments will build the pre-clinical foundation for testing AAV-mediated gene therapy with eCD4-Ig in infants as a means to prevent and treat perinatal HIV infection.