Targeting human dendritic cells via DEC-205 using PLGA nanoparticles leads to enhanced cross-presentation of a melanoma-associated antigen

Vaccine approaches to treat urothelial cancer

Bladder cancer (BC) accounts for about 4% of all malignancies. Non-muscle-invasive BC, 75% of cases, is treated with transurethral resection and adjuvant intravesical instillation, while muscle-invasive BC warrants cisplatin-based perioperative chemotherapy. Although immune-checkpoint inhibitors, antibody drug conjugates and targeted agents have provided dramatic advances, metastatic BC remains a generally incurable disease and clinical trials continue to vigorously evaluate novel molecules. Cancer vaccines aim at activating the patient's immune system against tumor cells. Several means of delivering neoantigens have been developed, including peptides, antigen-presenting cells, virus, or nucleic acids. Various improvements are constantly being explored, such as adjuvants use and combination strategies. Nucleic acids-based vaccines are increasingly gaining attention in recent years, with promising results in other malignancies. However, despite the recent advantages, numerous obstacles persist. This review is aimed at describing the different types of cancer vaccines, their evaluations in UC patients and the more recent innovations in this field.

Design Principles for Immunomodulatory Biomaterials

The immune system is imperative to the survival of all biological organisms. A functional immune system protects the organism by detecting and eliminating foreign and host aberrant molecules. Conversely, a dysfunctional immune system characterized by an overactive or weakened immune system causes life-threatening autoimmune or immunodeficiency diseases. Therefore, a critical need exists to develop technologies that regulate the immune system to ensure homeostasis or treat several diseases. Accumulating evidence shows that biomaterials─artificial materials (polymers, metals, ceramics, or engineered cells and tissues) that interact with biological systems─can trigger immune responses, offering a materials science-based strategy to modulate the immune system. This Review discusses the expanding frontiers of biomaterial-based immunomodulation, focusing on principles for designing these materials. This Review also presents examples of immunomodulatory biomaterials, which include polymers and metal- and carbon-based nanomaterials, capable of regulating the innate and adaptive immune systems.

Straight to the point: targeted mRNA-delivery to immune cells for improved vaccine design

With the deepening of our understanding of adaptive immunity at the cellular and molecular level, targeting antigens directly to immune cells has proven to be a successful strategy to develop innovative and potent vaccines. Indeed, it offers the potential to increase vaccine potency and/or modulate immune response quality while reducing off-target effects. With mRNA-vaccines establishing themselves as a versatile technology for future applications, in the last years several approaches have been explored to target nanoparticles-enabled mRNA-delivery systems to immune cells, with a focus on dendritic cells. Dendritic cells (DCs) are the most potent antigen presenting cells and key mediators of B- and T-cell immunity, and therefore considered as an ideal target for cell-specific antigen delivery. Indeed, improved potency of DC-targeted vaccines has been proved in vitro and in vivo. This review discusses the potential specific targets for immune system-directed mRNA delivery, as well as the different targeting ligand classes and delivery systems used for this purpose.

Nanovaccines: A game changing approach in the fight against infectious diseases

The field of nanotechnology has revolutionised global attempts to prevent, treat, and eradicate infectious diseases in the foreseen future. Nanovaccines have proven to be a valuable pawn in this novel technology. Nanovaccines are made up of nanoparticles that are associated with or prepared with components that can stimulate the host's immune system. In addition to their delivery capabilities, the nanocarriers have been demonstrated to possess intrinsic adjuvant properties, working as immune cell stimulators. Thus, nanovaccines have the potential to promote rapid as well as long-lasting humoral and cellular immunity. The nanovaccines have several possible benefits, including site-specific antigen delivery, increased antigen bioavailability, and a diminished adverse effect profile. To avail these benefits, several nanoparticle-based vaccines are being developed, including virus-like particles, liposomes, polymeric nanoparticles, nanogels, lipid nanoparticles, emulsion vaccines, exomes, and inorganic nanoparticles. Inspired by their distinctive properties, researchers are working on the development of nanovaccines for a variety of applications, such as cancer immunotherapy and infectious diseases. Although a few challenges still need to be overcome, such as modulation of the nanoparticle pharmacokinetics to avoid rapid elimination from the bloodstream by the reticuloendothelial system, The future prospects of this technology are also assuring, with multiple options such as personalised vaccines, needle-free formulations, and combination nanovaccines with several promising candidates.

Nanoparticles for vaccine and gene therapy: Overcoming the barriers to nucleic acid delivery

Nucleic acid therapeutics can be used to control virtually every aspect of cell behavior and therefore have significant potential to treat genetic disorders, infectious diseases, and cancer. However, while clinically approved to treat a small number of diseases, the full potential of nucleic acid therapeutics is hampered by inefficient delivery. Nucleic acids are large, highly charged biomolecules that are sensitive to degradation and so the approaches to deliver these molecules differ significantly from traditional small molecule drugs. Current studies suggest less than 1% of the injected nucleic acid dose is delivered to the target cell in an active form. This inefficient delivery increases costs and limits their use to applications where a small amount of nucleic acid is sufficient. In this review, we focus on two of the major barriers to efficient nucleic acid delivery: (1) delivery to the target cell and (2) transport to the subcellular compartment where the nucleic acids are therapeutically active. We explore how nanoparticles can be modified with targeting ligands to increase accumulation in specific cells, and how the composition of the nanoparticle can be engineered to manipulate or disrupt cellular membranes and facilitate delivery to the optimal subcellular compartments. Finally, we highlight how with intelligent material design, nanoparticle delivery systems have been developed to deliver nucleic acids that silence aberrant genes, correct genetic mutations, and act as both therapeutic and prophylactic vaccines. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Biology-Inspired Nanomaterials > Lipid-Based Structures.

Robust Antigen-Specific T Cell Activation within Injectable 3D Synthetic Nanovaccine Depots

Synthetic cancer vaccines may boost anticancer immune responses by co-delivering tumor antigens and adjuvants to dendritic cells (DCs). The accessibility of cancer vaccines to DCs and thereby the delivery efficiency of antigenic material greatly depends on the vaccine platform that is used. Three-dimensional scaffolds have been developed to deliver antigens and adjuvants locally in an immunostimulatory environment to DCs to enable sustained availability. However, current systems have little control over the release profiles of the cargo that is incorporated and are often characterized by an initial high-burst release. Here, an alternative system is designed that co-delivers antigens and adjuvants to DCs through cargo-loaded nanoparticles (NPs) incorporated within biomaterial-based scaffolds. This creates a programmable system with the potential for controlled delivery of their cargo to DCs. Cargo-loaded poly(d,l-lactic-co-glycolic acid) NPs are entrapped within the polymer walls of alginate cryogels with high efficiency while retaining the favorable physical properties of cryogels, including syringe injection. DCs cultured within these NP-loaded scaffolds acquire strong antigen-specific T cell-activating capabilities. These findings demonstrate that introduction of NPs into the walls of macroporous alginate cryogels creates a fully synthetic immunostimulatory niche that stimulates DCs and evokes strong antigen-specific T cell responses.

Design of Polymeric Carriers for Intracellular Peptide Delivery in Oncology Applications

In recent decades, peptides, which can possess high potency, excellent selectivity, and low toxicity, have emerged as promising therapeutics for cancer applications. Combined with an improved understanding of tumor biology and immuno-oncology, peptides have demonstrated robust antitumor efficacy in preclinical tumor models. However, the translation of peptides with intracellular targets into clinical therapies has been severely hindered by limitations in their intrinsic structure, such as low systemic stability, rapid clearance, and poor membrane permeability, that impede intracellular delivery. In this Review, we summarize recent advances in polymer-mediated intracellular delivery of peptides for cancer therapy, including both therapeutic peptides and peptide antigens. We highlight strategies to engineer polymeric materials to increase peptide delivery efficiency, especially cytosolic delivery, which plays a crucial role in potentiating peptide-based therapies. Finally, we discuss future opportunities for peptides in cancer treatment, with an emphasis on the design of polymer nanocarriers for optimized peptide delivery.

Nanoparticle-Mediated Targeted Drug Delivery to Remodel Tumor Microenvironment for Cancer Therapy

Advanced research has revealed the crucial role of tumor microenvironment (TME) in tumorigenesis. TME consists of a complicated network with a variety of cell types including endothelial cells, pericytes, immune cells, cancer-associated fibroblasts (CAFs), cancer stem cells (CSCs) as well as the extracellular matrix (ECM). The TME-constituting cells interact with the cancerous cells through plenty of signaling mechanisms and pathways in a dynamical way, participating in tumor initiation, progression, metastasis, and response to therapies. Hence, TME is becoming an attractive therapeutic target in cancer treatment, exhibiting potential research interest and clinical benefits. Presently, the novel nanotechnology applied in TME regulation has made huge progress. The nanoparticles (NPs) can be designed as demand to precisely target TME components and to inhibit tumor progression through TME modulation. Moreover, nanotechnology-mediated drug delivery possesses many advantages including prolonged circulation time, enhanced bioavailability and decreased toxicity over traditional therapeutic modality. In this review, update information on TME remodeling through NPs-based targeted drug delivery strategies for anticancer therapy is summarized.

The Crosstalk Between Dendritic Cells, Cytokine-Induced Killer Cells And Cancer Cells From The Perspective Of Combination Therapy

Dendritic cells (DCs) are considered the most potent professional antigen-presenting cells (APCs) that elicit adaptive antitumour immunity. DCs integrate multiple environmental signals by efficiently processing tumour-associated antigens (TAAs) and migrating to draining lymph nodes (dLNs), where they present foreign antigens to T cells for priming. DCs thus serve as a major link between innate and adaptive immunity. Although DCs (mostly monocyte-derived DCs [mo-DCs]) have already been used in cancer therapies, such approaches have shown limited efficacy. Mo-DCs have the unique ability to present antigens to T cells in peripheral tissues. CD3+CD56+ cytokine-induced killer (CIK) cells are characterized by both MHC-restricted and MHC-unrestricted antitumour cytotoxicity against a broad range of cancer cells. This review presents an overview of the mechanisms by which mo-DCs and CIK cells’ interact with each other and with tumours. The maturation of DCs was identified as a crucial step in the development of effective DC-based vaccines against cancer. A further improved adoptive immunotherapy strategy involves a combination of mature mo-DCs and CIK cells. Combination therapy presents many opportunities for cancer treatment, as reported by a number of clinical trials. However, there is a lack of fundamental studies on the interaction of in vitro-generated mo-DCs with CIK cells. We discuss several methods of boosting DC-based vaccines and review the current knowledge of contact-dependent and cytokine-induced interactions of mo-DCs with CIK cells. We highlight that the combination of mo-DCs with CIK cells activates MHC-restricted and MHC-unrestricted immune responses.

Therapeutic Liposomal Vaccines for Dendritic Cell Activation or Tolerance

Dendritic cells (DCs) are paramount in initiating and guiding immunity towards a state of activation or tolerance. This bidirectional capacity of DCs sets them at the center stage for treatment of cancer and autoimmune or allergic conditions. Accordingly, many clinical studies use ex vivo DC vaccination as a strategy to boost anti-tumor immunity or to suppress immunity by including vitamin D3, NF-κB inhibitors or retinoic acid to create tolerogenic DCs. As harvesting DCs from patients and differentiating these cells in vitro is a costly and cumbersome process, in vivo targeting of DCs has huge potential as nanoparticulate platforms equipped with activating or tolerogenic adjuvants can modulate DCs in their natural environment. There is a rapid expansion of the choices of nanoparticles and activation- or tolerance-promoting adjuvants for a therapeutic vaccine platform. In this review we highlight the most recent nanomedical approaches aimed at inducing immune activation or tolerance via targeting DCs, together with novel fundamental insights into the mechanisms inherent to fostering anti-tumor or tolerogenic immunity.

Biocompatibility of nanomaterials and their immunological properties

Nanomaterials (NMs) have revolutionized multiple aspects of medicine by enabling novel sensing, diagnostic, and therapeutic approaches. Advancements in processing and fabrication have also allowed significant expansion in the applications of the major classes of NMs based on polymer, metal/metal oxide, carbon, liposome, or multi-scale macro-nano bulk materials. Concomitantly, concerns regarding the nanotoxicity and overall biocompatibility of NMs have been raised. These involve putative negative effects on both patients and those subjected to occupational exposure during manufacturing. In this review, we describe the current state of testing of NMs including those that are in clinical use, in clinical trials, or under development. We also discuss the cellular and molecular interactions that dictate their toxicity and biocompatibility. Specifically, we focus on the reciprocal interactions between NMs and host proteins, lipids, and sugars and how these induce responses in immune and other cell types leading to topical and/or systemic effects.

Nanoparticles (PLGA and Chitosan)-Entrapped ADP-Ribosylation Factor 1 of Haemonchus contortus Enhances the Immune Responses in ICR Mice

ADP-ribosylation factor 1 (HcARF1) is one of the Haemonchus contortus (H. contortus) excretory/secretory proteins involved in modulating the immune response of goat peripheral blood mononuclear cells (PBMC). Here, we evaluated the immunogenic potential of recombinant HcARF1 (rHcARF1) against H. contortus infection in Institute of Cancer Research (ICR) mice. Briefly, rHcARF1 was entrapped in poly (D, L-lactide-co-glycolide) (PLGA) and chitosan (CS) nanoparticles (NP) and injected into mice as a vaccine. Fifty-six ICR mice were assigned randomly into seven groups, with eight animals in each group, and they were vaccinated subcutaneously. At the end of the experiment (14th day), the blood and the spleen were collected from euthanized mice to detect lymphocyte proliferation, cytokine analysis, and the production of antigen-specific antibodies. Scanning electron microscope was used to determine the size, morphology, and zeta potential of nanoparticles. Flow cytometry was performed, which presented the increase percentages of CD4+ T cells (CD3e+CD4+), CD8+ T cells (CD3e+CD8+) and dendritic cells (CD11c+CD83+, CD11c+CD86+) in mice vaccinated with rHcARF1+PLGA NP. Immunoassay analysis show raised humoral (Immunoglobulin (Ig)G1, IgG2a, IgM) and cell-mediated immune response (Interleukin (IL)-4, IL-12, and IL-17, and Interferon (IFN)-γ) induced by rHcARF1+PLGA NP. Experimental groups that were treated with the antigen-loaded NP yield higher lymphocyte proliferation than the control groups. Based on these results, we could propose that the rHcARF1 encapsulated in NP could stimulate a strong immune response in mice rather than administering alone against the infection of H. contortus.

Biomedical nanomaterials for immunological applications: ongoing research and clinical trials

Research efforts on nanomaterial-based therapies for the treatment of autoimmune diseases and cancer have spiked and have made rapid progress over the past years. Nanomedicine has been shown to contribute significantly to overcome current therapeutic limitations, exhibiting advantages compared to conventional therapeutics, such as sustained drug release, delayed drug degradation and site-specific drug delivery. Multiple nanodrugs have reached the clinic, but translation is often hampered by either low targeting efficiency or undesired side effects. Nanomaterials, and especially inorganic nanoparticles, have gained criticism due to their potential toxic effects, including immunological alterations. However, many strategies have been attempted to improve the therapeutic efficacy of nanoparticles and exploit their unique properties for the treatment of inflammation and associated diseases. In this review, we elaborate on the immunomodulatory effects of nanomaterials, with a strong focus on the underlying mechanisms that lead to these specific immune responses. Nanomaterials to be discussed include inorganic nanoparticles such as gold, silica and silver, as well as organic nanomaterials such as polymer-, dendrimer-, liposomal- and protein-based nanoparticles. Furthermore, various approaches for tuning nanomaterials in order to enhance their efficacy and attenuate their immune stimulation or suppression, with respect to the therapeutic application, are described. Additionally, we illustrate how the acquired insights have been used to design immunotherapeutic strategies for a variety of diseases. The potential of nanomedicine-based therapeutic strategies in immunotherapy is further illustrated by an up to date overview of current clinical trials. Finally, recent efforts into enhancing immunogenic cell death through the use of nanoparticles are discussed.

Protein-only nanocapsules induce cross-presentation in dendritic cells, demonstrating potential as an antigen delivery system

Templating has been demonstrated to be an efficient method of nanocapsule preparation. However, there have been no reports of using protein-only nanocapsules as an antigen delivery system. Such a system would enable the delivery of antigen without additional polymers. This study focused on defining the structural and cellular characteristics of nanocapsules consisting of antigen (ovalbumin) alone, synthesized by the templating method using highly monodispersed solid core mesoporous shell (SC/MS) and mesoporous (MS) silica nanoparticles of 410 nm and 41 nm in diameter, respectively. The synthesized ovalbumin nanocapsules were homogeneous in structure, and cellular uptake was observed in DC2.4 murine immature dendritic cells with minimal cytotoxicity. The nanocapsules were localized intracellularly and induced antigen presentation by the cross-presentation pathway. The templating system, using SC/MS and MS silica nanoparticles, was demonstrated to be an effective nanocapsule synthesis method for a new antigen delivery system.

Transcriptome Analysis Identifies Immune Markers Related to Visceral Leishmaniasis Establishment in the Experimental Model of BALB/c Mice

Visceral leishmaniasis (VL) caused by Leishmania donovani and L. infantum is a potentially fatal disease. To date there are no registered vaccines for disease prevention despite the fact that several vaccines are in preclinical development. Thus, new strategies are needed to improve vaccine efficacy based on a better understanding of the mechanisms mediating protective immunity and mechanisms of host immune responses subversion by immunopathogenic components of Leishmania. We found that mice vaccinated with CPA_162−189-loaded p8-PLGA nanoparticles, an experimental nanovaccine, induced the differentiation of antigen-specific CD8⁺ T cells in spleen compared to control mice, characterized by increased dynamics of proliferation and high amounts of IFN-γ production after ex vivo re-stimulation with CPA_162−189 antigen. Vaccination with CPA_162−189-loaded p8-PLGA nanoparticles resulted in about 80% lower parasite load in spleen and liver at 4 weeks after challenge with L. infantum promastigotes as compared to control mice. However, 16 weeks after infection the parasite load in spleen was comparable in both mouse groups. Decreased protection levels in vaccinated mice were followed by up-regulation of the anti-inflammatory IL-10 production although at lower levels in comparison to control mice. Microarray analysis in spleen tissue at 4 weeks post challenge revealed different immune-related profiles among the two groups. Specifically, vaccinated mice were characterized by similar profile to naïve mice. On the other hand, the transcriptome of the non-vaccinated mice was dominated by increased expression of genes related to interferon type I, granulocyte chemotaxis, and immune cells suppression. This profile was significantly enriched at 16 weeks post challenge, a time-point which is relative to disease establishment, and was common for both groups, further suggesting that type I signaling and granulocyte influx has a significant role in disease establishment, pathogenesis and eventually in decreased vaccine efficacy for stimulating long-term protection. Overall, we put a spotlight on host immune networks during active VL as potential targets to improve and design more effective vaccines against disease.

Biomimetic Nanoparticle Vaccines for Cancer Therapy

It is currently understood that, in order for a tumor to successfully grow, it must evolve means of evading immune surveillance. In the past several decades, researchers have leveraged increases in our knowledge of tumor immunology to develop therapies capable of augmenting endogenous immunity and eliciting strong antitumor responses. In particular, the goal of anticancer vaccination is to train the immune system to properly utilize its own resources in the fight against cancer. Although attractive in principle, there are currently only limited examples of anticancer vaccines that have been successfully translated to the clinic. Recently, there has been a significant push towards the use of nanotechnology for designing vaccine candidates that exhibit enhanced potency and specificity. In this progress report, we discuss recent developments in the field of anticancer nanovaccines. By taking advantage of the flexibility offered by nanomedicine to purposefully program immune responses, this new generation of vaccines has the potential to address many of the hurdles facing traditional platforms. A specific emphasis is placed on the emergence of cell membrane-coated nanoparticles, a novel biomimetic platform that can be used to generate personalized nanovaccines that elicit strong, multi-antigenic antitumor responses.

In-vitro Transcribed mRNA Delivery Using PLGA/PEI Nanoparticles into Human Monocyte-derived Dendritic Cells

Induction of protein synthesis by the external delivery of in-vitro transcription-messenger RNA (IVT-mRNA) has been a useful approach in the realm of cell biology, disease treatment, ‎reprogramming of cells, and vaccine design. Therefore, the development of new formulations for ‎protection of mRNA against nucleases is required to maintain its activity in-vivo. It was the aim of the present study to ‎investigate the uptake, toxicity, transfection efficiency as well as phenotypic consequences of ‎a nanoparticle (NP) in cell culture. NP consists of poly D, L-lactide-co-glycolide (PLGA) and polyethyleneimine (PEI) ‎for delivery of in-vitro transcription-messenger RNA (IVT- mRNA) encoded green fluorescent protein (GFP) in human monocyte-derived ‎dendritic cells (moDCs). Nanoparticles that were synthesized and encapsulated with synthetic GFP mRNA, exhibited size distribution in this formulation, with mean particle sizes ranging between 415 and 615 nm. Zeta potential was positive (above 12-13 mV) and the encapsulation efficiency exceeded 73.5%. Our results demonstrated that PLGA/PEI NPs encapsulation of GFP mRNA had ‎no toxic effect on immature monocyte-derived ‎dendritic cells and was capable of delivering of IVT-mRNA into moDCs and was highly effective. The expression of GFP protein 48 h after transfection was confirmed by flow cytometry, microscopic examination and western blotting assay. This NP can make a way to target moDCs to express a variety of antigens by IVT- mRNA. The ‎present study introduced the PLGA/PEI NP, which provided effective delivery of ‎IVT-mRNA that encodes the GFP protein.

Biomaterials for vaccine-based cancer immunotherapy

The development of therapeutic cancer vaccines as a means to generate immune reactivity against tumors has been explored since the early discovery of tumor-specific antigens by Georg Klein in the 1960s. However, challenges including weak immunogenicity, systemic toxicity, and off-target effects of cancer vaccines remain as barriers to their broad clinical translation. Advances in the design and implementation of biomaterials are now enabling enhanced efficacy and reduced toxicity of cancer vaccines by controlling the presentation and release of vaccine components to immune cells and their microenvironment. Here, we discuss the rational design and clinical status of several classes of cancer vaccines (including DNA, mRNA, peptide/protein, and cell-based vaccines) along with novel biomaterial-based delivery technologies that improve their safety and efficacy. Further, strategies for designing new platforms for personalized cancer vaccines are also considered.

Polymeric micro- and nanoparticles for immune modulation

New advances in biomaterial-based approaches to modulate the immune system are being applied to treat cancer, infectious diseases, and autoimmunity. Particulate systems are especially well-suited to deliver immunomodulatory factors to immune cells since their small size allows them to engage cell surface receptors or deliver cargo intracellularly after internalization. Biodegradable polymeric particles are a particularly versatile platform for the delivery of signals to the immune system because they can be easily surface-modified to target specific receptors and engineered to release encapsulated cargo in a precise, sustained manner. Micro- and nanoscale systems have been used to deliver a variety of therapeutic agents including monoclonal antibodies, peptides, and small molecule drugs that function to activate the immune system against cancer or infectious disease, or suppress the immune system to combat autoimmune diseases and transplant rejection. This review provides an overview of recent advances in the development of polymeric micro- and nanoparticulate systems for the presentation and delivery of immunomodulatory agents targeted to a variety of immune cell types including APCs, T cells, B cells, and NK cells.

Re-Emergence of Dendritic Cell Vaccines for Cancer Treatment

Dendritic cells (DCs) are essential in immunity owing to their role in activating T cells, thereby promoting antitumor responses. Tumor cells, however, hijack the immune system, causing T cell exhaustion and DC dysfunction. Tumor-induced T cell exhaustion may be reversed through immune checkpoint blockade (ICB); however, this treatment fails to show clinical benefit in many patients. While ICB serves to reverse T cell exhaustion, DCs are still necessary to prime, activate, and direct the T cells to target tumor cells. In this review we provide a brief overview of DC function, describe mechanisms by which DC functions are disrupted by the tumor microenvironment, and highlight recent developments in DC cancer vaccines.

LECTINS IN ANTI-CANCER STRATEGIES

The published during last few years data concerning communicative role of lectins (proteins and their complexes which recognize  carbohydrates, glycoconjugates and their patterns) in on-duty  supporting and increasing anticancer status of human immunity are  analyzed. Examples of lectin-(glycoconjugate pattern) strategies,  approaches and tactic variants in study and development of  anticancer treatments, principle variants of therapy, possible  vaccines in 35 cases of blood connected tumors (leukemia,  lymphomas, others), solid tumors (carcinomas, sarcoma, cancers of vaginal biotopes, prostate, bladder, colon, other intestinal  compartments, pancreas, liver, kidneys, others) and cancer cell lines  are described and systemized. The list of mostly used communicative lectins (pattern recognition receptors, their soluble forms, other  soluble lectins possessing specificities of importance) involving in key intercellular cascades and pathway co-functioning is presented. The  regulation of resulting expression of distinct active lectins (available and hetero/di/oligomeric forms) and their interaction to  adequate glycoconjugate patterns as well as influence distribution of  co-functioning lectins and antigens CD between populations and  subpopulations of antigen-presented cells (dendritic cells cDC, mDC,  moDC, pDC; macrophages M2 and M1), mucosal M-cells, NK-cells  play key role for choice and development of anticancer complex  procedures increasing innate and innate-coupled immune responses.  Prospects of (receptor lectin)-dependent intercellular  communications and targeting glycoconjugate constructions into  innate immunity cells for therapy of cancer and development of anticancer vaccines are evaluated and discussed.

Novel vaccines: Technology and development

The development and widespread use of vaccines, which are defined by the World Health Organization as "biological preparations that improve immunity to a particular disease," represents one of the most significant strides in medicine. Vaccination was first applied to reduce mortality and morbidity from infectious diseases. The World Health Organization estimates that vaccines prevent 2 to 3 million human deaths annually, and these numbers would increase by at least 6 million if all children received the recommended vaccination schedule. However, the origins of allergen immunotherapy share the same intellectual paradigm, and subsequent innovations in vaccine technology have been applied beyond the prevention of infection, including in the treatment of cancer and allergic diseases. This review will focus on how new and more rational approaches to vaccine development use novel biotechnology, target new mechanisms, and shape the immune system response, with an emphasis on discoveries that have direct translational relevance to the treatment of allergic diseases.

Latent, Immunosuppressive Nature of Poly(lactic-co-glycolic acid) Microparticles

Use of biomaterials to spatiotemporally control the activation of immune cells is at the forefront of biomedical engineering research. As more biomaterial strategies are employed for immunomodulation, understanding the immunogenicity of biodegradable materials and their byproducts is paramount in tailoring systems for immune activation or suppression. Poly(D,L-lactic-co-glycolic acid) (PLGA), one of the most commonly studied polymers in tissue engineering and drug delivery, has been previously described on one hand as an immune adjuvant, and on the other as a nonactivating material. In this study, the effect of PLGA microparticles (MPs) on the maturation status of murine bone marrow-derived dendritic cells (DCs), the primary initiators of adaptive immunity, was investigated to decipher the immunomodulatory properties of this biomaterial. Treatment of bone marrow-derived DCs from C57BL/6 mice with PLGA MPs led to a time dependent decrease in the maturation level of these cells, as quantified by decreased expression of the positive stimulatory molecules MHCII, CD80, and CD86 as well as the ability to resist maturation following challenge with lipopolysaccharide (LPS). Moreover, this immunosuppression was dependent on the molecular weight of the PLGA used to fabricate the MPs, as higher molecular weight polymers required longer incubation to produce comparable dampening of maturation molecules. These phenomena were correlated to an increase in lactic acid both intracellularly and extracellularly during DC/PLGA MP coculture, which is postulated to be the primary agent behind the observed immune inhibition. This hypothesis is supported by our results demonstrating that resistance to LPS stimulation may be due to the ability of PLGA MP-derived lactic acid to inhibit the phosphorylation of TAK1 and therefore prevent NF-κB activation. This work is significant as it begins to elucidate how PLGA, a prominent biomaterial with broad applications ranging from tissue engineering to pharmaceutics, could modulate the local immune environment and offers insight on engineering PLGA to exploit its evolving immunogenicity.

Regulation of the Cell Biology of Antigen Cross-Presentation

Antigen cross-presentation is an adaptation of the cellular process of loading MHC-I molecules with endogenous peptides during their biosynthesis within the endoplasmic reticulum. Cross-presented peptides derive from internalized proteins, microbial pathogens, and transformed or dying cells. The physical separation of internalized cargo from the endoplasmic reticulum, where the machinery for assembling peptide-MHC-I complexes resides, poses a challenge. To solve this problem, deliberate rewiring of organelle communication within cells is necessary to prepare for cross-presentation, and different endocytic receptors and vesicular traffic patterns customize the emergent cross-presentation compartment to the nature of the peptide source. Three distinct pathways of vesicular traffic converge to form the ideal cross-presentation compartment, each regulated differently to supply a unique component that enables cross-presentation of a diverse repertoire of peptides. Delivery of centerpiece MHC-I molecules is the critical step regulated by microbe-sensitive Toll-like receptors. Defining the subcellular sources of MHC-I and identifying sites of peptide loading during cross-presentation remain key challenges.

The comings and goings of MHC class I molecules herald a new dawn in cross-presentation

MHC class I (MHC-I) molecules are the centerpieces of cross-presentation. They are loaded with peptides derived from exogenous sources and displayed on the plasma membrane to communicate with CD8 T cells, relaying a message of tolerance or attack. The study of cross-presentation has been focused on the relative contributions of the vacuolar versus cytosolic pathways of antigen processing and the location where MHC-I molecules are loaded. While vacuolar processing generates peptides loaded onto vacuolar MHC-I molecules, how and where exogenous peptides generated by the proteasome and transported by TAP meet MHC-I molecules for loading has been a matter of debate. The source and trafficking of MHC-I molecules in dendritic cells have largely been ignored under the expectation that these molecules came from the Endoplasmic reticulum (ER) or the plasma membrane. New studies reveal a concentrated pool of MHC-I molecules in the endocytic recycling compartment (ERC). These pools are rapidly mobilized to phagosomes carrying microbial antigens, and in a signal-dependent manner under the control of Toll-like receptors. The phagosome becomes a dynamic hub receiving traffic from multiple sources, the ER-Golgi intermediate compartment for delivering the peptide-loading machinery and the ERC for deploying MHC-I molecules that alert CD8 T cells of infection.

The era of bioengineering: how will this affect the next generation of cancer immunotherapy?

Background

Immunotherapy consists of activating the patient’s immune system to fight cancer and has the great potential of preventing future relapses thanks to immunological memory. A great variety of strategies have emerged to harness the immune system against tumors, from the administration of immunomodulatory agents that activate immune cells, to therapeutic vaccines or infusion of previously activated cancer-specific T cells. However, despite great recent progress many difficulties still remain, which prevent the widespread use of immunotherapy. Some of these limitations include: systemic toxicity, weak immune cellular responses or persistence over time and most ultimately costly and time-consuming procedures.

Main body

Synthetic and natural biomaterials hold great potential to address these hurdles providing biocompatible systems capable of targeted local delivery, co-delivery, and controlled and/or sustained release. In this review we discuss some of the bioengineered solutions and approaches developed so far and how biomaterials can be further implemented to help and shape the future of cancer immunotherapy.

Conclusion

The bioengineering strategies here presented constitute a powerful toolkit to develop safe and successful novel cancer immunotherapies.

Dendritic Cell Targeting Effectively Boosts T Cell Responses Elicited by an HIV Multiepitope DNA Vaccine

Despite several efforts in the last decades, an efficacious HIV-1 vaccine is still not available. Different approaches have been evaluated, such as recombinant proteins, viral vectors, DNA vaccines, and, most recently, dendritic cell (DC) targeting. This strategy is based on DC features that place them as central for induction of immunity. Targeting is accomplished by the use of chimeric monoclonal antibodies directed to DC surface receptors fused to the antigen of interest. In this work, we targeted eight promiscuous HIV-derived CD4⁺ T cell epitopes (HIVBr8) to the DEC205⁺ DCs by fusing the multiepitope immunogen to the heavy chain of αDEC205 (αDECHIVBr8), in the presence of the TLR3 agonist poly (I:C). In addition, we tested a DNA vaccine encoding the same epitopes using homologous or heterologous prime-boost regimens. Our results showed that mice immunized with αDECHIVBr8 presented higher CD4⁺ and CD8⁺ T cell responses when compared to mice that received the DNA vaccine (pVAXHIVBr8). In addition, pVAXHIVBr8 priming followed by αDECHIVBr8 boosting induced higher polyfunctional proliferative and cytokine-producing T cell responses to HIV-1 peptides than homologous DNA immunization or heterologous αDEC prime/DNA boost. Based on these results, we conclude that homologous prime-boost and heterologous boosting immunization strategies targeting CD4⁺ epitopes to DCs are effective to improve HIV-specific cellular immune responses when compared to standalone DNA immunization. Moreover, our results indicate that antigen targeting to DC is an efficient strategy to boost immunity against a multiepitope immunogen, especially in the context of DNA vaccination.

Potential applications of nanoparticles in cancer immunotherapy

In recent years considerable progress has been made in the field of cancer immunotherapy whereby treatments that modulate the body's own immune system are used to combat cancer. This has the potential to not only elicit strong anti-cancer immune responses which can break pre-existing tolerance and help promote tumor regression, but could also induce immunological memory which may help prevent tumor recurrence. In order to ensure effective delivery of immunotherapeutic agents, such as vaccines, checkpoint inhibitors, chemotherapeutic agents and nucleic acids, a safe and effective delivery system is often required. One such approach is the use of multifunctional nanoparticles (NPs), such as liposomes, polymers, micelles, dendrimers, inorganic NPs, and hybrid NPs, which have the potential to combine the delivery of a diverse range of therapeutic immunomodulators thereby increasing the efficacy of tumor cell killing. This review focuses on recent progress in NP-mediated immunotherapy for the treatment of cancer.

Smart Radiation Therapy Biomaterials

Radiation therapy (RT) is a crucial component of cancer care, used in the treatment of over 50% of cancer patients. Patients undergoing image guided RT or brachytherapy routinely have inert RT biomaterials implanted into their tumors. The single function of these RT biomaterials is to ensure geometric accuracy during treatment. Recent studies have proposed that the inert biomaterials could be upgraded to "smart" RT biomaterials, designed to do more than 1 function. Such smart biomaterials include next-generation fiducial markers, brachytherapy spacers, and balloon applicators, designed to respond to stimuli and perform additional desirable functions like controlled delivery of therapy-enhancing payloads directly into the tumor subvolume while minimizing normal tissue toxicities. More broadly, smart RT biomaterials may include functionalized nanoparticles that can be activated to boost RT efficacy. This work reviews the rationale for smart RT biomaterials, the state of the art in this emerging cross-disciplinary research area, challenges and opportunities for further research and development, and a purview of potential clinical applications. Applications covered include using smart RT biomaterials for boosting cancer therapy with minimal side effects, combining RT with immunotherapy or chemotherapy, reducing treatment time or health care costs, and other incipient applications.

Biodegradable Polymeric Nanoparticles-Based Vaccine Adjuvants for Lymph Nodes Targeting

Vaccines have successfully eradicated a large number of diseases. However, some infectious diseases (such as HIV, Chlamydia trachomatis or Bacillus anthracis) keep spreading since there is no vaccine to prevent them. One way to overcome this issue is the development of new adjuvant formulations which are able to induce the appropriate immune response without sacrificing safety. Lymph nodes are the site of lymphocyte priming by antigen-presenting cells and subsequent adaptive immune response, and are a promising target for vaccine formulations. In this review, we describe the properties of different polymer-based (e.g., poly lactic-co-glycolic acid, poly lactic acid …) particulate adjuvants as innovative systems, capable of co-delivering immunopotentiators and antigens. We point out how these nanoparticles enhance the delivery of antigens, and how their physicochemical properties modify their uptake by antigen-presenting cells and their migration into lymph nodes. We describe why polymeric nanoparticles increase the persistence into lymph nodes and promote a mature immune response. We also emphasize how nanodelivery directs the response to a specific antigen and allows the induction of a cytotoxic immune response, essential for the fight against intracellular pathogens or cancer. Finally, we highlight the interest of the association between polymer-based vaccines and immunopotentiators, which can potentiate the effect of the molecule by directing it to the appropriate compartment and reducing its toxicity.

Emerging nanotechnologies for cancer immunotherapy

Founded on the growing insight into the complex cancer-immune system interactions, adjuvant immunotherapies are rapidly emerging and being adapted for the treatment of various human malignancies. Immune checkpoint inhibitors, for example, have already shown clinical success. Nevertheless, many approaches are not optimized, require frequent administration, are associated with systemic toxicities and only show modest efficacy as monotherapies. Nanotechnology can potentially enhance the efficacy of such immunotherapies by improving the delivery, retention and release of immunostimulatory agents and biologicals in targeted cell populations and tissues. This review presents the current status and emerging trends in such nanotechnology-based cancer immunotherapies including the role of nanoparticles as carriers of immunomodulators, nanoparticles-based cancer vaccines, and depots for sustained immunostimulation. Also highlighted are key translational challenges and opportunities in this rapidly growing field.

Recent Advances in Subunit Vaccine Carriers

The lower immunogenicity of synthetic subunit antigens, compared to live attenuated vaccines, is being addressed with improved vaccine carriers. Recent reports indicate that the physio-chemical properties of these carriers can be altered to achieve optimal antigen presentation, endosomal escape, particle bio-distribution, and cellular trafficking. The carriers can be modified with various antigens and ligands for dendritic cells targeting. They can also be modified with adjuvants, either covalently or entrapped in the matrix, to improve cellular and humoral immune responses against the antigen. As a result, these multi-functional carrier systems are being explored for use in active immunotherapy against cancer and infectious diseases. Advancing technology, improved analytical methods, and use of computational methodology have also contributed to the development of subunit vaccine carriers. This review details recent breakthroughs in the design of nano-particulate vaccine carriers, including liposomes, polymeric nanoparticles, and inorganic nanoparticles.

Peptide/protein vaccine delivery system based on PLGA particles

Due to the excellent safety profile of poly (D,L-lactide-co-glycolide) (PLGA) particles in human, and their biodegradability, many studies have focused on the application of PLGA particles as a controlled-release vaccine delivery system. Antigenic proteins/peptides can be encapsulated into or adsorbed to the surface of PLGA particles. The gradual release of loaded antigens from PLGA particles is necessary for the induction of efficient immunity. Various factors can influence protein release rates from PLGA particles, which can be defined intrinsic features of the polymer, particle characteristics as well as protein and environmental related factors. The use of PLGA particles encapsulating antigens of different diseases such as hepatitis B, tuberculosis, chlamydia, malaria, leishmania, toxoplasma and allergy antigens will be described herein. The co-delivery of antigens and immunostimulants (IS) with PLGA particles can prevent the systemic adverse effects of immunopotentiators and activate both dendritic cells (DCs) and natural killer (NKs) cells, consequently enhancing the therapeutic efficacy of antigen-loaded PLGA particles. We will review co-delivery of different TLR ligands with antigens in various models, highlighting the specific strengths and weaknesses of the system. Strategies to enhance the immunotherapeutic effect of DC-based vaccine using PLGA particles can be designed to target DCs by functionalized PLGA particle encapsulating siRNAs of suppressive gene, and disease specific antigens. Finally, specific examples of cellular targeting where decorating the surface of PLGA particles target orally administrated vaccine to M-cells will be highlighted.

A Combined Approach Employing Chlorotoxin-Nanovectors and Low Dose Radiation To Reach Infiltrating Tumor Niches in Glioblastoma

Glioblastoma multiforme (GBM) is the most aggressive form of glioma, with life expectancy of around 2 years after diagnosis, due to recidivism and to the blood-brain barrier (BBB) limiting the amount of drugs which reach the residual malignant cells, thus contributing to the failure of chemotherapies. To bypass the obstacles imposed by the BBB, we investigated the use of nanotechnologies combined with radiotherapy, as a potential therapeutic strategy for GBM. We used poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PNP) conjugated to chlorotoxin (CTX), a peptide reported to bind selectively to glioma cells. Silver nanoparticles were entrapped inside the functionalized nanoparticles (Ag-PNP-CTX), to allow detection and quantification of the cellular uptake by confocal microscopy, both in vitro and in vivo. In vitro experiments performed with different human glioblastoma cell lines showed higher cytoplasmic uptake of Ag-PNP-CTX, with respect to nonfunctionalized nanoparticles. In vivo experiments showed that Ag-NP-CTX efficiently targets the tumor, but are scarcely effective in crossing the blood brain barrier in the healthy brain, where dispersed metastatic cells are present. We show here that single whole brain X-ray irradiation, performed 20 h before nanoparticle injection, enhances the expression of the CTX targets, MMP-2 and ClC-3, and, through BBB permeabilization, potently increases the amount of internalized Ag-PNP-CTX even in dispersed cells, and generated an efficient antitumor synergistic effect able to inhibit in vivo tumor growth. Notably, the application of Ag-PNP-CTX to irradiated tumor cells decreases the extracellular activity of MMP-2. By targeting dispersed GBM cells and reducing MMP-2 activity, the combined use of CTX-nanovectors with radiotherapy may represent a promising therapeutic approach toward GBM.

Configuration-dependent Presentation of Multivalent IL-15:IL-15Rα Enhances the Antigen-specific T Cell Response and Anti-tumor Immunity

Here we report a "configuration-dependent" mechanism of action for IL-15:IL-15Rα (heterodimeric IL-15 or hetIL-15) where the manner by which IL-15:IL-15Rα molecules are presented to target cells significantly affects its function as a vaccine adjuvant. Although the cellular mechanism of IL-15 trans-presentation via IL-15Rα and its importance for IL-15 function have been described, the full effect of the IL-15:IL-15Rα configuration on responding cells is not yet known. We found that trans-presenting IL-15:IL-15Rα in a multivalent fashion on the surface of antigen-encapsulating nanoparticles enhanced the ability of nanoparticle-treated dendritic cells (DCs) to stimulate antigen-specific CD8(+) T cell responses. Localization of multivalent IL-15:IL-15Rα and encapsulated antigen to the same DC led to maximal T cell responses. Strikingly, DCs incubated with IL-15:IL-15Rα-coated nanoparticles displayed higher levels of functional IL-15 on the cell surface, implicating a mechanism for nanoparticle-mediated transfer of IL-15 to the DC surface. Using artificial antigen-presenting cells to highlight the effect of IL-15 configuration on DCs, we showed that artificial antigen-presenting cells presenting IL-15:IL-15Rα increased the sensitivity and magnitude of the T cell response, whereas IL-2 enhanced the T cell response only when delivered in a paracrine fashion. Therefore, the mode of cytokine presentation (configuration) is important for optimal immune responses. We tested the effect of configuration dependence in an aggressive model of murine melanoma and demonstrated significantly delayed tumor progression induced by IL-15:IL-15Rα-coated nanoparticles in comparison with monovalent IL-15:IL-15Rα. The novel mechanism of IL-15 transfer to the surface of antigen-processing DCs may explain the enhanced potency of IL-15:IL-15Rα-coated nanoparticles for antigen delivery.

Novel antigen delivery systems

Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the “E2 scaffold” of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus.

Small Wonders-The Use of Nanoparticles for Delivering Antigen

Despite the discovery of many potential antigens for subunit vaccines, universal protection is often lacking due to the limitations of conventional delivery methods. Subunit vaccines primarily induce antibody-mediated humoral responses, whereas potent antigen-specific cellular responses are required for prevention against some pathogenic infections. Nanoparticles have been utilised in nanomedicine and are promising candidates for vaccine or drug delivery. Nanoparticle vehicles have been demonstrated to be efficiently taken up by dendritic cells and induce humoral and cellular responses. This review provides an overview of nanoparticle vaccine development; in particular, the preparation of nanoparticles using a templating technique is highlighted, which would alleviate some of the disadvantages of existing nanoparticles. We will also explore the cellular fate of nanoparticle vaccines. Nanoparticle-based antigen delivery systems have the potential to develop new generation vaccines against currently unpreventable infectious diseases.