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After over 3 decades of research, an effective anti-HIV vaccine remains elusive. The recently halted HVTN702 clinical trial not only further stresses the challenge to develop an effective HIV vaccine but also emphasizes that unconventional and novel vaccine strategies are urgently needed. Here, we report that a vaccine focusing the immune response on the sequences surrounding the 12 viral protease cleavage sites (PCSs) provided greater than 80% protection to Mauritian cynomolgus macaques against repeated intravaginal SIVmac251 challenges. The PCS-specific T cell responses correlated with vaccine efficacy. The PCS vaccine did not induce immune activation or inflammation known to be associated with increased susceptibility to HIV infection. Machine learning analyses revealed that the immune microenvironment generated by the PCS vaccine was predictive of vaccine efficacy. Our study demonstrates, for the first time to our knowledge, that a vaccine which targets only viral maturation, but lacks full-length Env and Gag immunogens, can prevent intravaginal infection in a stringent macaque/SIV challenge model. Targeting HIV maturation thus offers a potentially novel approach to developing an effective HIV vaccine.

Studies have shown that vaccine vectors and route of immunization can differentially activate different arms of the immune system. However, the effects of different HIV vaccine immunogens on mucosal inflammation have not yet been studied. Because mucosal sites are the primary route of HIV infection, we evaluated the cervico-vaginal inflammatory cytokine and chemokine levels of Mauritian cynomolgus macaques following immunization and boost using two different SIV vaccine immunogens. The PCS vaccine delivers 12 20-amino acid peptides overlapping the 12 protease cleavage sites, and the Gag/Env vaccine delivers the full Gag and full Env proteins of simian immunodeficiency virus. We showed that the PCS vaccine prime and boosts induced short-lived, lower level increases of a few pro-inflammatory/chemotactic cytokines. In the PCS-vaccine group only the levels of MCP-1 were significantly increased above the baseline (P = 0.0078, Week 6; P = 0.0078, Week 17; P = 0.0234; Week 51) following multiple boosts. In contrast, immunizations with the Gag/Env vaccine persistently increased the levels of multiple cytokines/chemokines. In the Gag/Env group, higher than baseline levels were consistently observed for IL-8 (P = 0.0078, Week 16; P = 0.0078, Week 17; P = 0.0156, Week 52), IL-1β (P = 0.0234, Week 16; P = 0.0156, Week 17; P = 0.0156, Week 52), and MIP-1α (P = 0.0313, Week 16; P = 0.0156, Week 17; P = 0.0313, Week 52). Over time, repeated boosts altered the relative levels of these cytokines between the Gag/Env and PCS vaccine group. 18 weeks after final boost with a higher dosage, IP-10 levels (P = 0.0313) in the Gag/Env group remained higher than baseline. Thus, the influence of vaccine immunogens on mucosal inflammation needs to be considered when developing and evaluating candidate HIV vaccines.

Background: Tumor-associated macrophages (TAMs), with M2-like immunosuppressive profiles, are key players in the development and dissemination of tumors. Hence, the induction of M1 pro-inflammatory and anti-tumoral states is critical to fight against cancer cells. The activation of the endosomal toll-like receptor 3 by its agonist poly(I:C) has shown to efficiently drive this polarization process. Unfortunately, poly(I:C) presents significant systemic toxicity, and its clinical use is restricted to a local administration. Therefore, the objective of this work has been to facilitate the delivery of poly(I:C) to macrophages through the use of nanotechnology, that will ultimately drive their phenotype toward pro-inflammatory states. Methods: Poly(I:C) was complexed to arginine-rich polypeptides, and then further enveloped with an anionic polymeric layer either by film hydration or incubation. Physicochemical characterization of the nanocomplexes was conducted by dynamic light scattering and transmission electron microscopy, and poly(I:C) association efficiency by gel electrophoresis. Primary human-derived macrophages were used as relevant in vitro cell model. Alamar Blue assay, ELISA, PCR and flow cytometry were used to determine macrophage viability, polarization, chemokine secretion and uptake of nanocomplexes. The cytotoxic activity of pre-treated macrophages against PANC-1 cancer cells was assessed by flow cytometry. Results: The final poly(I:C) nanocomplexes presented sizes lower than 200 nm, with surface charges ranging from +40 to −20 mV, depending on the envelopment. They all presented high poly(I:C) loading values, from 12 to 50%, and great stability in cell culture media. In vitro, poly(I:C) nanocomplexes were highly taken up by macrophages, in comparison to the free molecule. Macrophage treatment with these nanocomplexes did not reduce their viability and efficiently stimulated the secretion of the T-cell recruiter chemokines CXCL10 and CCL5, of great importance for an effective anti-tumor immune response. Finally, poly(I:C) nanocomplexes significantly increased the ability of treated macrophages to directly kill cancer cells. Conclusion: Overall, these enveloped poly(I:C) nanocomplexes might represent a therapeutic option to fight cancer through the induction of cytotoxic M1-polarized macrophages.

Despite a very active research in the field of nanomedicine, only a few nano-based drug delivery systems have reached the market. The “death valley” between research and commercialization has been partially attributed to the limited characterization and reproducibility of the nanoformulations. Our group has previously reported the potential of a peptide-based nanovaccine candidate for the prevention of SIV infection in macaques. This vaccine candidate is composed of chitosan/dextran sulfate nanoparticles containing twelve SIV peptide antigens. The aim of this work was to rigorously characterize one of these nanoformulations containing a specific peptide, following a quality-by-design approach. The evaluation of the different quality attributes was performed by several complementary techniques, such as dynamic light scattering, nanoparticle tracking analysis, and electron microscopy for particle size characterization. The inter-batch reproducibility was validated by three independent laboratories. Finally, the long-term stability and scalability of the manufacturing technique were assessed. Overall, these data, together with the in vivo efficacy results obtained in macaques, underline the promise this new vaccine holds with regard to its translation to clinical trials This work was supported by the European Union’s Horizon 2020 research program (NanoPilot project – grant agreement number 646142) and by Xunta de Galicia’s Grupos de referencia competitiva (grant number ED431C 2017/09). T.G. Dacoba acknowledges a predoctoral FPU grant from the Spanish Ministry of Education, Culture and Sports (grant number FPU14/05866) SI

Nowadays, nanotechnology-based modulation of the immune system is presented as a cutting-edge strategy, which may lead to significant improvements in the treatment of severe diseases. In particular, efforts have been focused on the development of nanotechnology-based vaccines, which could be used for immunization or generation of tolerance. In this review, we highlight how different immune responses can be elicited by tuning nanosystems properties. In addition, we discuss specific formulation approaches designed for the development of anti-infectious and anti-autoimmune vaccines, as well as those intended to prevent the formation of antibodies against biologicals.

After over three decades of research, an effective anti-HIV vaccine remains elusive. Unconventional and novel vaccine strategies are needed. Here, we report that a vaccine focusing the immune response on the sequences surrounding the 12 viral protease cleavage sites (PCSs) provides greater than 80% protection of Mauritian cynomolgus macaques (MCMs) against repeated intravaginal SIVmac251 challenges. The PCS-specific T cell responses are correlated with vaccine efficacy. The PCS vaccine does not induce immune activation and inflammation known to be associated with increased susceptibility to HIV infection. Machine learning analyses revealed that the immune environment generated by the PCS vaccine predicts vaccine efficacy. Our study demonstrates for the first time that a novel vaccine which targets viral maturation, but lacks full Env and Gag proteins as immunogens, can prevent intravaginal infection in a highly stringent NHP/SIV challenge model. Targeting HIV maturation thus offers a novel approach to developing an effective HIV vaccine.One Sentence SummaryThe anti-PCS T cell responses and the immune environment induced by the novel PCS vaccine are key correlates of vaccine efficacy

High grade gliomas (HGG) are the most common malignant brain tumor in children, and remain effectively incurable with 5 year overall survival. We developed a library of functionalized nanoparticles (NPs) with ligands targeting BBB shuttle mechanisms. Using the layer-by-layer (LbL) platform to functionally ‘wrap’ polyelectrolytes around a NP core by iterative electrostatic adsorption, we can incorporate a wide range of drugs, modulate release kinetics, and add targeting moieties in a highly tunable system. In this study, we layered a liposomal core with alkyne-modified poly-L-aspartic acid or hyaluronic acid, and functionalized the surface with BBB ligands glutathione (GSH), angiopep-2 (AP2), or transferrin (Tf). Functionalization improved NP uptake in endothelial cells and lowered the IC50 of encapsulated cisplatin in HGG cells over control NPs. To investigate the ability of functionalized NPs to effectively cross the BBB and penetrate tumor cells, we incorporated HGG spheroids into a microfluidic model of co-cultured human astrocytes, pericytes, and induced pluripotent stem cell (iPSC) endothelial cells, which self-assemble into perfusable microvascular networks (µVNs) with properties comparable to the human BBB (Campisi et al. Biomaterials 2018). After perfusing fluorescent LbL NPs into µVNs with and without HGG spheroids, we quantified vascular permeability and found higher overall permeability in spheroid-containing networks. NPs functionalized with AP2 and Tf exhibited higher BBB transit than non-functionalized NPs in networks with and without HGG spheroids. In this work, we establish a new model for testing drug delivery across the BBB and identified promising functionalized drug carriers for HGG. Ongoing studies in murine models are underway to further validate this platform for clinical translation.

International audience; Nanoformulations are complex systems where physicochemical properties determine their therapeutic efficacy and safety. In the case of nanovaccines, particle size and shape play a crucial role on the immune response generated. Furthermore, the antigen's integrity is also a key aspect to control when producing a nanovaccine. The determination of all those physicochemical properties is still an analytical challenge and the lack of well-established methods hinders the access of new therapeutics to the market. In this work, robust methods for the characterization of a novel HIV nanoparticle-based vaccine produced in good manufacturing practice (GMPs)-like environment were developed. With slightly polydisperse particles (< 0.2) close to 180 nm of size, batch-mode Dynamic Light Scattering (DLS) was validated to be used as a quality control technique in the pilot production plant. In addition, a high size resolution method using Asymmetrical Flow Field Flow Fractionation (AF4) demonstrated its ability to determine not only size and size distribution but also shape modification across the size and accurate quantification of the free active ingredient. Results showed a monomodal distribution of particles from 60 to 700 nm, most of them (> 90%) with size lower than 250 nm, consistent with more traditional techniques, and revealed a slight change in the structure of the particles induced by the presence of the antigen. Finally, a batch to batch variability lower than 20% was obtained by both DLS and AF4 methods indicating that preparation method was highly reproducible.

Platinum-based agents remain a key component of therapy for children with medulloblastoma, despite significant systemic side effects and only modest blood-brain barrier (BBB) penetration. Cisplatin has a cerebrospinal fluid-to-plasma ratio

HIV mutates rapidly and infects CD4+ T cells, especially when they are activated. A vaccine targeting conserved, essential viral elements while limiting CD4+ T cell activation could be effective. Learning from natural immunity observed in a group of highly HIV-1 exposed seronegative Kenyan female sex workers, we are testing a novel candidate HIV vaccine targeting the 12 viral protease cleavage sites (PCSs) (the PCS vaccine), in comparison with a vaccine targeting full-length Gag and Env (the Gag/Env vaccine) in a Mauritian cynomolgus macaque/SIV model. In this study we evaluated these vaccines for induction of mucosal antibodies to SIV immunogens at the female genital tract. Bio-Plex and Western blot analyses of cervicovaginal lavage samples showed that both the PCS and Gag/Env vaccines can elicit mucosal IgG antibody responses to SIV immunogens. Significantly higher increase of anti-PCS antibodies was induced by the PCS vaccine than by the Gag/Env vaccine (p

The development of an effective HIV vaccine continues to be a major health challenge since, so far, only the RV144 trial has demonstrated a modest clinical efficacy. Recently, the targeting of the 12 highly conserved protease cleavage sites (PCS1–12) has been presented as a strategy seeking to hamper the maturation and infectivity of HIV. To pursue this line of research, and because peptide antigens have low immunogenicity, we have included these peptides in engineered nanoparticles, aiming at overcoming this limitation. More specifically, we investigated whether the covalent attachment of a PCS peptide (PCS5) to polysaccharide-based nanoparticles, and their coadministration with polyinosinic:polycytidylic acid (poly(I:C)), improved the generated immune response. To this end, PCS5 was first conjugated to two different polysaccharides (chitosan and hyaluronic acid) through either a stable or a cleavable bond and then associated with an oppositely charged polymer (dextran sulfate and chitosan) and poly(I:C) to form the nanoparticles. Nanoparticles associating PCS5 by ionic interactions were used in this study as the control formulation. In vivo, all nanosystems elicited high anti-PCS5 antibodies. Nanoparticles containing PCS5 conjugated and poly(I:C) seemed to induce the strongest activation of antigen-presenting cells. Interestingly, T cell activation presented different kinetics depending on the prototype. These findings show that both the nanoparticle composition and the conjugation of the HIV peptide antigen may play an important role in the generation of humoral and cellular responses This work was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health (Award No. R01AI111805, Subaward No. 41795-02) and by the European Union’s Horizon 2020 research program (NanoPilot project, Grant Agreement No. 646142). T.G.D. acknowledges a predoctoral FPU grant from the Spanish Ministry of Education, Culture and Sports (Grant No. FPU14/05866) SI