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分离株所使用的CCR 5辅助受体，该受体负责主要传播。已经使用允许筛选数百万个CCR 5结合分子的创新噬菌体展示选择过程鉴定了两种具有抗CCR 5-使用HIV-1分离物的抗病毒活性的主要候选物，其等同于完全合成的PSC-RANTES。这些分子之一共享PSC-RANTES、CCR 5内化和螯合的抑制机制，并且还共享经由CCR 5的信号传导活性。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CCR 5内化或通过CCR 5进行信号传导。这些特性可以提高这种分子的安全性。该提案的R21阶段的目标是确定两种分子的活性机制、化合物去除后的活性持续时间以及对来自撒哈拉以南非洲的进化枝A、C和D原发性传播分离株的活性。我们还将尝试在体外产生对两种分子的抗性变体，并比较分子对低pH、高温和暴露于宫颈阴道灌洗液（CVL）的稳定性。将选择这些实验中具有最佳性质组合的分子，用于在雌性恒河猴中使用SHIV 162 P3阴道激发模型在R33阶段进行临床前评价。这些实验将确定预防传播的有效剂量，确定该剂量是否能防止延迟的病毒攻击，并评估局部炎症和促炎细胞因子的诱导作为安全性指标。将评价从接受治疗的迟发性病毒血症动物中回收的病毒是否对主要RANTES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CCR 5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的局部杀微生物剂。

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.