Development of a Vaccine for HIV-AIDS: Translation to the Clinic

NIH 临床中心与 NIAID 和首席研究员 Mark Connors 博士合作，启动了具有复制能力的 Ad4-HIVenv 和 Ad4-HIVmosaic gag 疫苗的 I 期临床试验。该研究正在评估口服肠溶胶囊和上呼吸道液体疫苗的安全性和免疫原性。与此同时，在恒河猴模型中进行临床前评估后，正在开发新的具有复制能力的 Ad 载体，以供未来的临床使用。对小鼠的研究和对恒河猴的初步研究表明，删除了 E1B55K 和/或 E4orf1-4 或 E4orf1 早期区域基因的 Ad-HIV 包膜重组体不仅具有更大的携带能力，而且表现出增强的细胞和体液免疫。这些试点研究将确定用于后续临床前疫苗研究的最佳载体，以评估整体免疫原性和保护功效。一项正在进行的恒河猴临床前疫苗研究调查了粘膜系统联合疫苗方案。这两种疫苗方案都没有导致接种疫苗的猕猴延迟获得 SIV，但这部分是由于先天免疫记忆（所谓的“训练免疫”）的发展。我们目前正在利用 RNA seq 研究和单核细胞/巨噬细胞的流式细胞术研究进一步研究这种反应，以强化结论。尽管没有获得延迟获得，但我们确实观察到接种疫苗的雌性猕猴而不是雄性猕猴的急性病毒血症略有下降。我们之前报道过 SIV 疫苗诱导的保护存在性别偏见，当前的这一发现证实了这一观察结果。在这里，我们发现性别之间的差异很大程度上是由于直肠微生物组的差异，这些差异受到疫苗方案的影响，进而影响免疫反应。目前的一项针对猕猴的临床前研究正在评估一种新型疫苗/杀菌剂方案。杀微生物剂已被证明可以有效预防艾滋病毒传播，然而，其有效性取决于适当的使用，而这往往会受到人类行为的影响。我们假设，在未正确使用杀菌剂的情况下，将预防性疫苗与杀菌剂相结合可能会提供针对感染的保护。因此，我们用 Ad 重组引发/Env 蛋白加强方案对恒河猴进行免疫，以引发粘膜免疫，并随后在施用杀菌剂后将接种疫苗的动物暴露于传染性 SIV。杀微生物剂 (SAMT-247) 是一种锌指抑制剂，可导致非感染性病毒颗粒的表达，但其表面仍具有完整的包膜。我们假设非传染性颗粒将增强疫苗方案已经引起的免疫反应。总体而言，我们正在测试这样的假设：疫苗加杀菌剂联合治疗方案通过提供针对 SIV 感染的附加或协同保护是有益的。迄今为止，我们发现杀微生物剂非常有效，并且可以改善仅通过疫苗获得的保护。最后，我们最近报道了使用 nanoFACS 从临床样本中分选和表征 HIV/SIV 的新技术的开发。可以根据掺入病毒颗粒中的细胞抗原或使用针对不同包膜表位的特异性抗体对病毒颗粒进行染色和分选。从临床相关样本中分选传染性 HIV 的能力为详细的分子、遗传和蛋白质组学分析提供了材料，这些分析适用于未来的疫苗抗原设计和个性化治疗方案的潜在开发。

A phase I clinical trial of replication-competent Ad4-HIVenv and Ad4-HIVmosaic gag vaccines was initiated in the NIH clinical center in collaboration with NIAID and Dr. Mark Connors as Principal Investigator. The study is evaluating the safety and immunogenicity of the vaccines formulated as enteric coated capsules for oral administration and as a liquid for administration to the upper respiratory tract. At the same time, new replication-competent Ad vectors are under development for future clinical use following pre-clinical evaluation in the rhesus macaque model. Studies in mice and pilot studies in rhesus macaques have shown that Ad-HIV envelope recombinants with deletions of E1B55K and/or E4orf1-4 or E4orf1 early region genes not only have greater carrying capacity but also exhibit enhanced cellular and humoral immunity. These pilot studies will identify the optimal vector for use in subsequent pre-clinical vaccine studies evaluating overall immunogenicity and protective efficacy. An on-going pre-clinical vaccine study in rhesus macaques has investigated combination mucosal-systemic vaccine regimens. Neither vaccine regimen induced delayed SIV acquisition in vaccinated macaques, but this was partly due to development of innate immune memory (so-called "trained immunity"). We are currently investigating this response further using RNA seq studies and flow cytometry investigation of monocyte/macrophages to strengthen the conclusion. Although delayed acquisition was not obtained, we did observe modestly decreased acute viremia attributed to the vaccinated female macaques rather than the males. We previously reported a sex bias in SIV vaccine induced protection, and this current finding confirms the observation. Here, we have found the difference between the sexes is largely due to rectal microbiome differences which are affected by the vaccine regimen and in turn influence immune responses. A current pre-clinical study in macaques is evaluating a novel vaccine/microbicide regimen. Microbicides have been shown to be effective in preventing HIV transmission, however, their effectiveness depends on appropriate use which is often compromised by human behavior. We hypothesized that combining a prophylactic vaccine with a microbicide might provide protection against infection in instances when microbicides are not used properly. Therefore, we immunized rhesus macaques with our Ad-recombinant priming/Env protein boosting regimen in order to elicit mucosal immunity and subsequently exposed the vaccinated animals to infectious SIV following administration of a microbicide. The microbicide (SAMT-247) is a zinc finger inhibitor that results in expression of non-infectious viral particles which nevertheless have intact envelope on their surface. We have postulated that the non-infectious particles will boost the immune response already elicited by the vaccine regimen. Overall, we are testing the hypothesis that the combined vaccine plus microbicide regimen is beneficial by providing either additive or synergistic protection against SIV infection. To date we have found that the microbicide is highly effective and improves the protection obtained with the vaccine only. Finally, we recently reported the development of a new technology for sorting and characterization of HIV/SIV from clinical specimens using nanoFACS. The virions can be stained and sorted based on either cellular antigens incorporated into the virion particles or alternatively using specific antibodies to different envelope epitopes. The ability to sort infectious HIV from clinically relevant samples provides material for detailed molecular, genetic, and proteomic analyses applicable to future design of vaccine antigens and potential development of personalized treatment regimens.