Recombinant CCR5 Inhibitors for Topical Microbicides

描述（由申请人提供）：该R21/R33阶段创新奖申请建议开发能够重组表达的新型RANTES衍生物作为候选局部杀微生物剂。这些分子靶向HIV-1分离株用于初次传播的CCR5共受体。使用与完全合成的PSC-RANTES相当的HIV-1分离物，已经通过一种创新的噬菌体展示选择过程确定了两个具有抗CCR5抗病毒活性的主要候选物，该过程允许筛选数百万个CCR5结合分子。其中一种分子共享PSC-RANTES、CCR5内化和封存的抑制机制，并通过CCR5共享信号传导活性。第二种分子虽然在抑制病毒感染方面同样有效，但不会引起CCR5内化或通过CCR5发出信号。这些特性可以提高该分子的安全性。R21阶段的目标是确定这两个分子的活性机制，化合物去除后的活性持续时间，以及对撒哈拉以南非洲A、C和D进化支原传播分离株的活性。我们还将尝试在体外产生对这两种分子的抗性变体，并比较分子在低pH值、高温和暴露于宫颈阴道灌洗液（CVL）中的稳定性。在这些实验中，我们将选择具有最佳组合特性的分子进行R33期临床前评估，使用SHIV162P3雌性恒河猴阴道攻击模型。这些实验将确定预防传播的有效剂量，确定该剂量是否可以防止延迟病毒攻击，并评估局部炎症和促炎细胞因子的诱导作为安全性指标。将评估从患有延迟病毒血症的治疗动物身上恢复的病毒是否对RANTES铅衍生物产生耐药性。这些研究旨在开发一种安全、有效和廉价的蛋白质CCR5抑制剂，用于受全球艾滋病毒/艾滋病流行影响最严重的地区。

DESCRIPTION (provided by applicant): This R21/R33 Phased Innovation Award application proposes to develop novel RANTES derivatives capable of recombinant expression as candidate topical microbicides. These molecules target the CCR5 coreceptor used by HIV-1 isolates responsible for primary transmission. Two lead candidates with antiviral activity against CCR5-using HIV-1 isolates equivalent to the fully synthetic PSC-RANTES have been identified using an innovative phage display selection process that allows screening of millions of CCR5 binding molecules. One of these molecules shares the inhibitory mechanism of PSC-RANTES, CCR5 internalization and sequestration, and also shares signaling activity via CCR5. The second molecule, although equally potent at inhibiting virus infection, does not cause CCR5 internalization or signaling via CCR5. These properties could improve the safety profile of this molecule. The objectives of the R21 phase of the proposal are to determine the mechanism of activity of the two molecules, the duration of activity after compound removal, and the activity against clade A, C, and D primary transmission isolates from sub- Saharan Africa. We will also attempt to generate resistant variants to both molecules in vitro, and compare the stability of the molecules to low pH, high temperature, and exposure to cervicovaginal lavage (CVL) fluid. The molecule with the best combination of properties in these experiments will be selected for preclinical evaluation in the R33 phase using the SHIV162P3 vaginal challenge model in female rhesus macaques. These experiments will establish the effective dose for preventing transmission, determine if that dose protects against delayed virus challenge, and evaluate local inflammation and induction of proinflammatory cytokines as indicators of safety. Virus recovered from treated animals with delayed viremia will be evaluated for development of resistance to the lead RANTES derivative. These studies are designed to lead to a safe, effective, and inexpensive protein CCR5 inhibitor for incorporation into a topical microbicide for use in areas most impacted by the global HIV/AIDS pandemic.