Kasturi Sudhir Pai, Kozlowski Pamela A, Nakaya Helder I, Burger Matheus C, Russo Pedro, Pham Mathew, Kovalenkov Yevgeniy, Silveira Eduardo L V, Havenar-Daughton Colin, Burton Samantha L, Kilgore Katie M, Johnson Mathew J, Nabi Rafiq, Legere Traci, Sher Zarpheen Jinnah, Chen Xuemin, Amara Rama R, Hunter Eric, Bosinger Steven E, Spearman Paul, Crotty Shane, Villinger Francois, Derdeyn Cynthia A, Wrammert Jens, Pulendran Bali
Emory Vaccine Center/Yerkes National Primate Research Center at Emory University, Atlanta, Georgia, USA.
Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
J Virol. 2017 Jan 31;91(4). doi: 10.1128/JVI.01844-16. Print 2017 Feb 15.
Our previous work has shown that antigens adjuvanted with ligands specific for Toll-like receptor 4 (TLR4) and TLR7/8 encapsulated in poly(lactic-co-glycolic) acid (PLGA)-based nanoparticles (NPs) induce robust and durable immune responses in mice and macaques. We investigated the efficacy of these NP adjuvants in inducing protective immunity against simian immunodeficiency virus (SIV). Rhesus macaques (RMs) were immunized with NPs containing TLR4 and TLR7/8 agonists mixed with soluble recombinant SIVmac239-derived envelope (Env) gp140 and Gag p55 (protein) or with virus-like particles (VLPs) containing SIVmac239 Env and Gag. NP-adjuvanted vaccines induced robust innate responses, antigen-specific antibody responses of a greater magnitude and persistence, and enhanced plasmablast responses compared to those achieved with alum-adjuvanted vaccines. NP-adjuvanted vaccines induced antigen-specific, long-lived plasma cells (LLPCs), which persisted in the bone marrow for several months after vaccination. NP-adjuvanted vaccines induced immune responses that were associated with enhanced protection against repeated low-dose, intravaginal challenges with heterologous SIVsmE660 in animals that carried TRIM5α restrictive alleles. The protection induced by immunization with protein-NP correlated with the prechallenge titers of Env-specific IgG antibodies in serum and vaginal secretions. However, no such correlate was apparent for immunization with VLP-NP or alum as the adjuvant. Transcriptional profiling of peripheral blood mononuclear cells isolated within the first few hours to days after primary vaccination revealed that NP-adjuvanted vaccines induced a molecular signature similar to that induced by the live attenuated yellow fever viral vaccine. This systems approach identified early blood transcriptional signatures that correlate with Env-specific antibody responses in vaginal secretions and protection against infection. These results demonstrate the adjuvanticity of the NP adjuvant in inducing persistent and protective antibody responses against SIV in RMs with implications for the design of vaccines against human immunodeficiency virus (HIV).
The results of the RV144 HIV vaccine trial, which demonstrated a rapid waning of protective immunity with time, have underscored the need to develop strategies to enhance the durability of protective immune responses. Our recent work in mice has highlighted the capacity of nanoparticle-encapsulated TLR ligands (NP) to induce potent and durable antibody responses that last a lifetime in mice. In the present study, we evaluated the ability of these NP adjuvants to promote robust and durable protective immune responses against SIV in nonhuman primates. Our results demonstrate that immunization of rhesus macaques with NP adjuvants mixed with soluble SIV Env or a virus-like particle form of Env (VLP) induces potent and durable Env-specific antibody responses in the serum and in vaginal secretions. These responses were superior to those induced by alum adjuvant, and they resulted in enhanced protection against a low-dose intravaginal challenge with a heterologous strain of SIV in animals with TRIM5a restrictive alleles. These results highlight the potential for such NP TLR L adjuvants in promoting robust and durable antibody responses against HIV in the next generation of HIV immunogens currently being developed.
我们之前的研究表明，封装在聚乳酸 - 乙醇酸共聚物（PLGA）纳米颗粒（NP）中的、与Toll样受体4（TLR4）和TLR7/8特异性配体佐剂结合的抗原，可在小鼠和猕猴体内诱导强烈且持久的免疫反应。我们研究了这些NP佐剂在诱导针对猿猴免疫缺陷病毒（SIV）的保护性免疫方面的功效。将含有TLR4和TLR7/8激动剂的NP与可溶性重组SIVmac239来源的包膜（Env）gp140和Gag p55（蛋白）混合，或与含有SIVmac239 Env和Gag的病毒样颗粒（VLP）一起免疫恒河猴（RM）。与明矾佐剂疫苗相比，NP佐剂疫苗诱导了强烈的先天反应、更强且更持久的抗原特异性抗体反应以及增强的浆母细胞反应。NP佐剂疫苗诱导了抗原特异性的长寿浆细胞（LLPC），这些细胞在接种疫苗后在骨髓中持续存在数月。NP佐剂疫苗诱导的免疫反应与携带TRIM5α限制性等位基因的动物针对异源SIVsmE660的反复低剂量阴道攻击的增强保护相关。用蛋白 - NP免疫诱导的保护作用与血清和阴道分泌物中Env特异性IgG抗体的攻击前滴度相关。然而，对于用VLP - NP或明矾作为佐剂进行免疫，没有明显的这种相关性。在初次接种疫苗后的最初几小时至几天内分离的外周血单核细胞的转录谱分析表明，NP佐剂疫苗诱导的分子特征类似于减毒活黄热病病毒疫苗诱导的特征。这种系统方法确定了与阴道分泌物中Env特异性抗体反应和抗感染保护相关的早期血液转录特征。这些结果证明了NP佐剂在诱导恒河猴针对SIV产生持久和保护性抗体反应方面的佐剂活性，这对设计针对人类免疫缺陷病毒（HIV）的疫苗具有重要意义。
RV144 HIV疫苗试验的结果表明，保护性免疫会随着时间迅速减弱，这凸显了制定增强保护性免疫反应持久性策略的必要性。我们最近在小鼠中的研究强调了纳米颗粒封装的TLR配体（NP）诱导在小鼠体内持续一生的强效且持久抗体反应的能力。在本研究中，我们评估了这些NP佐剂在促进针对非人类灵长类动物中SIV的强大且持久保护性免疫反应方面的能力。我们的结果表明，用与可溶性SIV Env或Env的病毒样颗粒形式（VLP）混合的NP佐剂免疫恒河猴，可在血清和阴道分泌物中诱导强效且持久的Env特异性抗体反应。这些反应优于明矾佐剂诱导的反应，并导致在具有TRIM5a限制性等位基因的动物中针对异源SIV株的低剂量阴道攻击的保护增强。这些结果突出了此类NP TLR L佐剂在促进针对目前正在开发的下一代HIV免疫原的强大且持久抗体反应方面的潜力。
