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

在NIAID和Mark Connors博士作为首席研究员的合作下，NIH临床中心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。该研究正在评估两种疫苗的安全性和免疫原性，这两种疫苗配制为肠溶包衣胶囊用于口服，液体用于上呼吸道给药。与此同时，在恒河猴模型的临床前评估之后，新的具有复制能力的Ad载体正在开发中，用于未来的临床应用。小鼠研究和恒河猴的初步研究表明，E1B55K和/或E4orf1-4或E4orf1早期区域基因缺失的Ad-HIV包膜重组体不仅具有更大的携带能力，而且还表现出增强的细胞和体液免疫。这些试点研究将确定最佳载体，用于随后的临床前疫苗研究，评估总体免疫原性和保护功效。一项正在恒河猴进行的临床前疫苗研究调查了粘膜-全身联合疫苗方案。两种疫苗方案都没有在接种过疫苗的猕猴中诱导SIV获得延迟，但这部分是由于先天免疫记忆的发展（所谓的“训练免疫”）。我们目前正在利用RNA序列研究和单核细胞/巨噬细胞流式细胞术研究进一步研究这种反应，以加强结论。虽然没有延迟获得，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减少。我们之前报道了SIV疫苗诱导保护的性别偏见，目前的发现证实了这一观察结果。在这里，我们发现两性之间的差异主要是由于直肠微生物组的差异，而直肠微生物组的差异受疫苗方案的影响，进而影响免疫反应。目前在猕猴中进行的一项临床前研究正在评估一种新的疫苗/杀微生物剂方案。杀微生物剂已被证明在预防艾滋病毒传播方面是有效的，然而，其有效性取决于适当使用，而适当使用往往受到人类行为的影响。我们假设，在杀微生物剂使用不当的情况下，将预防性疫苗与杀微生物剂结合使用可能提供预防感染的保护。因此，我们用我们的ad重组引物/Env蛋白增强方案对恒河猴进行免疫，以引发粘膜免疫，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，可导致表面具有完整包膜的非感染性病毒颗粒的表达。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。总的来说，我们正在测试这样一种假设，即疫苗加杀微生物剂联合方案通过提供针对SIV感染的附加或协同保护而有益。到目前为止，我们发现杀微生物剂非常有效，可以提高仅用疫苗获得的保护。最后，我们最近报道了一项新技术的发展，该技术使用纳米facs从临床标本中分选和表征HIV/SIV。病毒粒子可以根据结合到病毒粒子中的细胞抗原或使用针对不同包膜表位的特异性抗体进行染色和分类。从临床相关样本中分选感染性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，适用于未来疫苗抗原的设计和个性化治疗方案的潜在发展。

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.