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，启动了可复制的Ad4-HIVenv和Ad4-HIVMosaic Gag疫苗的I期临床试验。该研究正在评估作为口服肠溶胶囊和作为上呼吸道液体给药的疫苗的安全性和免疫原性。同时，在恒河猴模型的临床前评估后，新的复制能力强的Ad载体正在开发中，用于未来的临床应用。对小鼠的研究和对猕猴的初步研究表明，缺失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强的携带能力，而且具有增强的细胞和体液免疫能力。这些试点研究将确定用于随后的临床前疫苗研究的最佳载体，以评估总体免疫原性和保护效果。一项正在进行的恒河猴临床前疫苗研究探索了黏膜-全身联合疫苗方案。两种疫苗方案都不会导致接种疫苗的猕猴延迟获得SIV，但这在一定程度上是由于天生免疫记忆的发展(即所谓的“训练免疫”)。我们目前正在使用RNA序列研究和单核/巨噬细胞的流式细胞术研究来进一步研究这一反应，以加强这一结论。虽然没有获得延迟获得，但我们确实观察到急性病毒血症的适度减少归因于接种疫苗的雌性猕猴而不是雄性猕猴。我们之前曾报道过SIV疫苗诱导的保护作用存在性别偏见，目前的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群的差异，这些微生物群受到疫苗方案的影响，进而影响免疫反应。目前一项针对猕猴的临床前研究正在评估一种新的疫苗/杀微生物剂方案。杀菌剂已被证明在预防艾滋病毒传播方面是有效的，然而，它们的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，将预防性疫苗与杀微生物剂相结合，可能会在杀菌剂使用不当的情况下提供预防感染的保护。因此，我们用我们的Ad-重组免疫/Env蛋白增强方案免疫恒河猴，以诱导粘膜免疫，并在注射杀菌剂后将接种的动物暴露于感染性SIV。杀微生物剂(SAMT-247)是一种锌指抑制剂，可导致非传染性病毒颗粒的表达，但其表面仍有完整的包膜。我们推测，非传染性颗粒将增强疫苗方案已经引发的免疫反应。总体而言，我们正在测试这样一种假设，即联合疫苗和杀微生物剂方案通过提供对SIV感染的添加剂或协同保护而有益。到目前为止，我们已经发现这种杀微生物剂是高效的，并改善了仅使用疫苗获得的保护。最后，我们最近报道了一种使用纳米FACS从临床标本中分离和鉴定HIV/SIV的新技术的开发。病毒粒子可以根据加入到病毒粒子中的细胞抗原进行染色和分类，或者使用针对不同包膜表位的特定抗体进行分类。从临床相关样本中分离传染性艾滋病毒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疫苗抗原的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.