Targeted delivery systems for biological therapies of inflammatory diseases

Pulmonary inhalation for disease treatment: Basic research and clinical translations

Pulmonary drug delivery has the advantages of being rapid, efficient, and well-targeted, with few systemic side effects. In addition, it is non-invasive and has good patient compliance, making it a highly promising drug delivery mode. However, there have been limited studies on drug delivery via pulmonary inhalation compared with oral and intravenous modes. This paper summarizes the basic research and clinical translation of pulmonary inhalation drug delivery for the treatment of diseases and provides insights into the latest advances in pulmonary drug delivery. The paper discusses the processing methods for pulmonary drug delivery, drug carriers (with a focus on various types of nanoparticles), delivery devices, and applications in pulmonary diseases and treatment of systemic diseases (e.g., COVID-19, inhaled vaccines, diagnosis of the diseases, and diabetes mellitus) with an updated summary of recent research advances. Furthermore, this paper describes the applications and recent progress in pulmonary drug delivery for lung diseases and expands the use of pulmonary drugs for other systemic diseases.

Discovery of WD-890: A novel allosteric TYK2 inhibitor for the treatment of multiple autoimmune diseases

Tyrosine kinase 2 (TYK2) as a member of Janus kinase (JAK) family, mainly mediates the signaling of type I interferons (IFN), interleukin-12 (IL-12) and interleukin-23 (IL-23), which has become an attractive target for treatment of immune and inflammatory diseases. However, the development of selective TYK2 inhibitors is challenging due to the high homology of the catalytic kinase domain among the JAK family members. Here, we report a novel and potent allosteric inhibitor, WD-890, which binds to the pseudokinase domain of TYK2 with high selectivity and inhibits its function. We accomplished a series of preclinical studies to demonstrate the therapeutic efficacy of WD-890 in four animal models: systemic lupus erythematosus (SLE), psoriasis, psoriatic arthritis (PsA), and inflammatory bowel disease (IBD). The pharmacokinetic and toxicology results further indicate that WD-890 has favorable absorption, distribution, metabolism, and excretion (ADME) properties and tolerable toxicity. In conclusion, our study shows that WD-890 could be a promising oral TYK2 inhibitor for future treatment of autoimmune diseases.

Smart redox-sensitive micelles based on chitosan for dasatinib delivery in suppressing inflammatory diseases

Dasatinib (DAS) exhibits anti-inflammatory effects by retrieving the balance between inflammatory and anti-inflammatory cytokines secreted by macrophages. The aim of this study was the development of redox-responsive micelles with the potential of passive targeting and on-demand drug release for DAS delivery to macrophages. For this purpose, two molecular weights of chitosan (CHIT) were conjugated to DAS at different molar ratios using 3,3'-dithiodipropionic anhydride (DTDPA) as disulfide bond containing linker to synthesize a series of CHIT-S-S-DAS amphiphilic conjugates. Micelles obtained by the sonication method had particle sizes of 129.3-172.2 nm, zeta potentials of +17.5 to +20.9 mV, drug contents of 0.90-7.20 %, CMC values of 35.3-96.6 μg/ml, and exhibited redox-responsive in vitro drug release. Optimized micelles were non-toxic and dramatically more efficient than non-redox responsive micelles in reducing TNF-α and IL-6 and increasing IL-10 secretion from LPS-stimulated RAW264.7 cells. Furthermore, the redox-responsive micelles were able to reduce the mice paw edema, reduce the plasma levels of pro-inflammatory cytokines and increase plasma level of IL-10, considerably more than free DAS and non-redox responsive micelles in carrageenan-induced mice paw edema model of inflammation.

Bionized Nanoferrite Particles Alter the Course of Experimental Cryptococcus neoformans Pneumonia

Cryptococcosis is a devastating fungal disease associated with high morbidity and mortality even when treated with antifungal drugs. Bionized nanoferrite (BNF) nanoparticles are powerful immunomodulators, but their efficacy for infectious diseases has not been investigated. Administration of BNF nanoparticles to mice with experimental cryptococcal pneumonia altered the outcome of infection in a dose response manner as measured by CFU and survival. The protective effects were higher at lower doses, with reductions in IL-2, IL-4, and TNF-α, consistent with immune modulation whereby reductions in inflammation translate into reduced host damage, clearance of infection, and longer survival.

Mesoporous silica nanoparticles for pulmonary drug delivery

Over the last years, respiratory diseases represent a clinical concern, being included among the leading causes of death in the world due to the lack of effective lung therapies, mainly ascribed to the pulmonary barriers affecting the delivery of drugs to the lungs. In this way, nanomedicine has arisen as a promising approach to overcome the limitations of current therapies for pulmonary diseases. The use of nanoparticles allows enhancing drug bioavailability at the target site while minimizing undesired side effects. Despite different approaches have been developed for pulmonary delivery of drugs, including the use of polymers, lipid-based nanoparticles, and inorganic nanoparticles, more efforts are required to achieve effective pulmonary drug delivery. This review provides an overview of the clinical challenges in main lung diseases, as well as highlighted the role of nanomedicine in achieving efficient pulmonary drug delivery. Drug delivery into the lungs is a complex process limited by the anatomical, physiological and immunological barriers of the respiratory system. We discuss how nanomedicine can be useful to overcome these pulmonary barriers and give insights for the rational design of future nanoparticles for enhancing lung treatments. We also attempt herein to display more in detail the potential of mesoporous silica nanoparticles (MSNs) as promising nanocarrier for pulmonary drug delivery by providing a comprehensive overview of their application in lung delivery to date while discussing the use of these particles for the treatment of respiratory diseases.

MicroRNA-223 modulates the IL-4-medicated macrophage M2-type polarization to control the progress of sepsis

MicroRNAs play a variety of roles in the progress of inflammation. Herein, we investigated the roles of miR-223 in governing macrophage polarization balance in the progress of sepsis. We firstly observed that miR-223 was down-regulated at the early phase and up-regulated at the late phase of sepsis in macrophages; the levels of miR-223 were positively correlated to the ratio of M2 macrophages during sepsis. In miR-223 knockout mice, we observed that miR-223 was dispensable for efficient pro-inflammatory responses, but was required for efficient M2-associated phenotype and function. miR-223 deletion increased clinical scores of sepsis, leading to increased mortality in septic mice. Furthermore, we found that miR-223 expression in M2-type macrophages was controlled by interleukin (IL)-4, but not IL-10; IL-4 antibodies were able to downregulate the levels of miR-223, increased the expression of targeted genes Nfat5 and Rasa1, reduced the ratio of M2 macrophages, resulting in a decreased survival rate in septic mice. Meanwhile, miR-223 deficient macrophages appeared a markedly decreased M2-type polarization when induced by IL-4, but did not affect macrophages skew to M2 phenotype induced by IL-10. Taken together, our results demonstrate that miR-223 acts as an important regulator to modulate IL-4-meditated M2-type polarization of macrophages via targeting to Nfat5 and Rasa1 to control the progress of sepsis.

Gold nanoparticles coated with polyvinylpyrrolidone and sea urchin extracellular molecules induce transient immune activation

We report that the immunogenicity of colloidal gold nanoparticles coated with polyvinylpyrrolidone (PVP-AuNPs) in a model organism, the sea urchin Paracentrotus lividus, can function as a proxy for humans for in vitro immunological studies. To profile the immune recognition and interaction from exposure to PVP-AuNPs (1 and 10 μg mL^-1), we applied an extensive nano-scale approach, including particle physicochemical characterisation involving immunology, cellular biology, and metabolomics. The interaction between PVP-AuNPs and soluble proteins of the sea urchin physiological coelomic fluid (blood equivalent) results in the formation of a protein "corona" surrounding the NPs from three major proteins that influence the hydrodynamic size and colloidal stability of the particle. At the lower concentration of PVP-AuNPs, the P. lividus phagocytes show a broad metabolic plasticity based on the biosynthesis of metabolites mediating inflammation and phagocytosis. At the higher concentration of PVP-AuNPs, phagocytes activate an immunological response involving Toll-like receptor 4 (TLR4) signalling pathway at 24 hours of exposure. These results emphasise that exposure to PVP-AuNPs drives inflammatory signalling by the phagocytes and the resolution at both the low and high concentrations of the PVP-AuNPs and provides more details regarding the immunogenicity of these NPs.

Bioresponsive drug delivery systems for the treatment of inflammatory diseases

Inflammation is intimately related to the pathogenesis of numerous acute and chronic diseases like cardiovascular disease, inflammatory bowel disease, rheumatoid arthritis, and neurodegenerative diseases. Therefore anti-inflammatory therapy is a very promising strategy for the prevention and treatment of these inflammatory diseases. To overcome the shortcomings of existing anti-inflammatory agents and their traditional formulations, such as nonspecific tissue distribution and uncontrolled drug release, bioresponsive drug delivery systems have received much attention in recent years. In this review, we first provide a brief introduction of the pathogenesis of inflammation, with an emphasis on representative inflammatory cells and mediators in inflammatory microenvironments that serve as pathological fundamentals for rational design of bioresponsive carriers. Then we discuss different materials and delivery systems responsive to inflammation-associated biochemical signals, such as pH, reactive oxygen species, and specific enzymes. Also, applications of various bioresponsive drug delivery systems in the treatment of typical acute and chronic inflammatory diseases are described. Finally, crucial challenges in the future development and clinical translation of bioresponsive anti-inflammatory drug delivery systems are highlighted.

A Novel Bivalent Mannosylated Targeting Ligand Displayed on Nanoparticles Selectively Targets Anti-Inflammatory M2 Macrophages

Persistent activation of macrophages (MP)s into a proinflammatory M1 or anti-inflammatory M2 phenotype plays a role in several pathological conditions, including autoimmune diseases, fibrosis, infections, atherosclerosis and tumor development. The mannose receptor (MR, CD206), expressed at low levels on resting MPs and absent on M1 MPs, is highly expressed on M2 MPs, making it a potential target and drug delivery portal. Recently, we developed a novel, highly selective MR targeting ligand (MRTL), consisting of two mannose molecules separated by a monodisperse 12 unit poly(ethylene glycol) linker, to enhance the cellular uptake of polymeric nanocarriers. The feasibility of using the MRTL ligand for selectively targeting M2 MPs for intracellular delivery of nanoparticles (NPs) was investigated. Rat peritoneal MPs were differentiated into an M1 or M2 phenotype using IFN-γ and IL-4/IL-13, respectively. Expression of the M1 marker, inducible nitric oxide synthase (iNOS), and the M2 markers arginase (Arg)-1 and MR (at both the mRNA and protein levels) confirmed MP phenotypic activation. Resting, M1 and M2 MPs were treated with fluorescein isothiocyanate (FITC)-labeled MRTL or NPs displaying FITC-labeled MRTL at two surface densities (1 and 10%) and examined by confocal microscopy. Intracellular fluorescence was also quantified. Uptake of the MRTL was 2.4- and 11.8-fold higher in M2 MPs when compared to resting or M1 MPs, respectively, consistent with marker expression levels. Mannan, a competitive inhibitor of the MR, abrogated MRTL uptake. MRTL also co-localized with a fluid-phase endocytosis marker, further suggesting that uptake was mediated by MR-mediated endocytosis. Intracellular NP fluorescence was confirmed by flow cytometry and by confocal microscopy. MRTL-NPs accumulated intracellularly with no significant cell surface binding, suggesting efficient translocation. NPs displaying a low surface density (1%) of the MRTL exhibited significantly higher (2.3-fold) uptake into M2 MPs, relative to resting and M1 MPs. The 10% MRTL-NPs displayed greater uptake by M2 MPs when compared to resting and M1 MPs, but less uptake than 1% MRTL-NPs into M2 MPs. Control FITC-labeled plain NPs did not exhibit selective MP uptake. These studies demonstrate that M2 MPs are selectively targeted by NPs displaying a novel bivalent ligand that utilizes the MR as a target/portal for cell entry. This study also establishes the feasibility of the approach allowing for further investigation in vivo.

Potential application of liposomal nanodevices for non-cancer diseases: an update on design, characterization and biopharmaceutical evaluation

Liposomes, lipid-based vesicular systems, have attracted major interest as a means to improve drug delivery to various organs and tissues in the human body. Recent literature highlights the benefits of liposomes for use as drug delivery systems, including encapsulating of both hydrophobic and hydrophilic cargos, passive and active targeting, enhanced drug bioavailability and therapeutic effects, reduced systemic side effects, improved cargo penetration into the target tissue and triggered contents release. Pioneering work of liposomes researchers led to introduction of long-circulating, ligand-targeted and triggered release liposomes, as well as, liposomes containing nucleic acids and vesicles containing combination of cargos. Altogether, these findings have led to widespread application of liposomes in a plethora of areas from cancer to conditions such as cardiovascular, neurologic, respiratory, skin, autoimmune and eye disorders. There are numerous review articles on the application of liposomes in treatment of cancer, which seems the primary focus, whereas other diseases also benefit from liposome-mediated treatments. Therefore, this article provides an illustrated detailed overview of liposomal formulations, in vitro characterization and their applications in different disorders other than cancer. Challenges and future directions, which must be considered to obtain the most benefit from applications of liposomes in these disorders, are discussed.

Targeting strategies of liposomal subunit vaccine delivery systems to improve vaccine efficacy

Liposomes are versatile delivery systems and immunological adjuvants that not only can load various antigens, such as proteins, peptides, nucleic acids and carbohydrates, but also can combine them with immunostimulators. Liposomes have great potential in the development of new types of vaccines, and much effort has been devoted to enhancing vaccine efficacy in recent years. Different types of immune cells such as macrophages and dendritic cells play an important role in the immune response and in preventing or treating cancer, allergy or many other infectious diseases. Targeting liposome-based delivery systems to certain immune cells and organs is one of the most effective measures in such treatments. Extensive research has shown that liposomes combined with immunostimulators or modified with pattern recognition receptor ligands can target various immune cells and the lymphatic system, thus not only inducing and promoting the desired immune response but also decreasing adverse effects throughout the body and avoiding targeting irrelevant cell types or tissues. Therefore, in this review, we outline some targeting strategies that can be adopted in the design of liposomal vaccines to improve vaccine efficacy, and we summarise the related liposome-based vaccine applications in several diseases. These applications have great potential to treat or prevent some infectious and intractable diseases.

Modulating the immune system through nanotechnology

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.

Vascular endothelial growth factor A amplification in colorectal cancer is associated with reduced M1 and M2 macrophages and diminished PD-1-expressing lymphocytes

VEGFA is an angiogenic factor secreted by tumors, in particular those with VEGFA amplification, as well as by macrophages and lymphocytes in the tumor microenvironment. Here we sought to define the presence of M1/M2 macrophages, PD-1-positive lymphocytes and PD-L1 tumoral and stromal expression in colorectal cancers harboring VEGFA amplification or chromosome 6 polysomy. 38 CRCs of which 13 harbored VEGFA amplification, 6 with Chr6 polysomy and 19 with neutral VEGFA copy number were assessed by immunohistochemistry for CD68 (marker for M1/M2 macrophages), CD163 (M2 macrophages), programmed death 1(PD-1)- tumor infiltrating and stromal lymphocytes as well as tumoral and stromal PD-1 ligand (PD-L1) expression. CRCs with VEGFA amplification or Chr6 polysomy were associated with decreased M1/M2 macrophages, reduced PD-1-expressing lymphocyte infiltration, as well as reduced stromal expression of PD-L1 at the tumor front. Compared to intermediate-grade CRCs, high-grade CRCs were associated with increased M1/M2 macrophages and increased tumoral expression of PD-L1. Our results suggest that VEGFA amplification or Chr6 polysomy is associated with an altered tumor immune microenvironment.

Transport patterns of anti-TNF-α in burn wounds: Therapeutic implications of hyaluronic acid conjugation

A central complication in burn injuries is progression of the zone of necrosis, which is associated with intense inflammatory responses. Conjugation of monoclonal antibodies against tumor necrosis factor-α (TNF-α), a central mediator of inflammation, to high molecular weight hyaluronic acid (HA) has been shown to be an effective treatment in reducing secondary necrosis in rodent models of deep partial-thickness burns. Here the transport of conjugated and non-conjugated antibodies in burn injuries was investigated to explore the effects of antibody tethering on the spatiotemporal distribution of anti-TNF-α. Diffusion constants were measured in solution and in type I collagen gels in vitro using fluorescence correlation spectroscopy to provide quantitative comparisons of the effects of conjugation. It is shown that the HA significantly increased the antibody residence time in the superficial region at 24 h in burn injuries, which strongly correlated with the pattern of inflammatory cell infiltrate in the tissue. A transport model was used to fit the results of antibody distribution in the tissue based on fluorescence correlation spectroscopy measurements, resulting in estimates for effective diffusion constants that demonstrate the effects of HA conjugation on the biodistribution of therapeutic proteins. These results demonstrate that tuning residence time of therapeutic proteins can be an effective strategy in regulating the inflammatory response associated with acute injuries.

Diversification and enrichment of clinical biomaterials inspired by Darwinian evolution

Regenerative medicine and biomaterials design are driven by biomimicry. There is the essential requirement to emulate human cell, tissue, organ and physiological complexity to ensure long-lasting clinical success. Biomimicry projects for biomaterials innovation can be re-invigorated with evolutionary insights and perspectives, since Darwinian evolution is the original dynamic process for biological organisation and complexity. Many existing human inspired regenerative biomaterials (defined as a nature generated, nature derived and nature mimicking structure, produced within a biological system, which can deputise for, or replace human tissues for which it closely matches) are without important elements of biological complexity such as, hierarchy and autonomous actions. It is possible to engineer these essential elements into clinical biomaterials via bioinspired implementation of concepts, processes and mechanisms played out during Darwinian evolution; mechanisms such as, directed, computational, accelerated evolutions and artificial selection contrived in the laboratory. These dynamos for innovation can be used during biomaterials fabrication, but also to choose optimal designs in the regeneration process. Further evolutionary information can help at the design stage; gleaned from the historical evolution of material adaptations compared across phylogenies to changes in their environment and habitats. Taken together, harnessing evolutionary mechanisms and evolutionary pathways, leading to ideal adaptations, will eventually provide a new class of Darwinian and evolutionary biomaterials. This will provide bioengineers with a more diversified and more efficient innovation tool for biomaterial design, synthesis and function than currently achieved with synthetic materials chemistry programmes and rational based materials design approach, which require reasoned logic. It will also inject further creativity, diversity and richness into the biomedical technologies that we make. All of which are based on biological principles. Such evolution-inspired biomaterials have the potential to generate innovative solutions, which match with existing bioengineering problems, in vital areas of clinical materials translation that include tissue engineering, gene delivery, drug delivery, immunity modulation, and scar-less wound healing.

STATEMENT OF SIGNIFICANCE

Evolution by natural selection is a powerful generator of innovations in molecular, materials and structures. Man has influenced evolution for thousands of years, to create new breeds of farm animals and crop plants, but now molecular and materials can be molded in the same way. Biological molecules and simple structures can be evolved, literally in the laboratory. Furthermore, they are re-designed via lessons learnt from evolutionary history. Through a 3-step process to (1) create variants in material building blocks, (2) screen the variants with beneficial traits/properties and (3) select and support their self-assembly into usable materials, improvements in design and performance can emerge. By introducing biological molecules and small organisms into this process, it is possible to make increasingly diversified, sophisticated and clinically relevant materials for multiple roles in biomedicine.

Current understanding of interactions between nanoparticles and the immune system

The delivery of drugs, antigens, and imaging agents benefits from using nanotechnology-based carriers. The successful translation of nanoformulations to the clinic involves thorough assessment of their safety profiles, which, among other end-points, includes evaluation of immunotoxicity. The past decade of research focusing on nanoparticle interaction with the immune system has been fruitful in terms of understanding the basics of nanoparticle immunocompatibility, developing a bioanalytical infrastructure to screen for nanoparticle-mediated immune reactions, beginning to uncover the mechanisms of nanoparticle immunotoxicity, and utilizing current knowledge about the structure-activity relationship between nanoparticles' physicochemical properties and their effects on the immune system to guide safe drug delivery. In the present review, we focus on the most prominent pieces of the nanoparticle-immune system puzzle and discuss the achievements, disappointments, and lessons learned over the past 15years of research on the immunotoxicity of engineered nanomaterials.

MicroRNA-223 Induced Repolarization of Peritoneal Macrophages Using CD44 Targeting Hyaluronic Acid Nanoparticles for Anti-Inflammatory Effects

The aim of this study was to evaluate macrophages repolarization from pro-inflammatory M1 to anti-inflammatory M2 phenotype upon transfection with microRNA-223 (miR-223) duplexes and miR-223 expressing plasmid DNA encapsulated in CD44-targeting hyaluronic acid-poly(ethyleneimine) (HA-PEI) nanoparticles (NPs). The HA-PEI/miR-223 NPs with spherical shape and an average diameter of 200 nm were efficiently internalized by J774A.1 alveolar and primary peritoneal macrophages and non-cytotoxic at HA-PEI concentration less than 200 μg/mL. Transfection of HA-PEI/miR-223 NPs in J774A.1 macrophages showed significantly higher miR-223 expression than that with HA-PEI/plasmid DNA expressing miR-223 (pDNA-miR-223). HA-PEI/miR-223 NPs mediated transfection increased miR-223 expression to 90 fold in primary peritoneal macrophages compared to untreated cells. The overexpression of miR-223 in both J774A.1 and peritoneal macrophages induced a phenotypic change from M1 to M2 state as indicated by a decrease in iNOS-2 (M1 marker) and an increase in Arg-1 (M2 marker) levels compared to those in lipopolysaccharide (LPS) and interferon-gamma (IFN-γ)-stimulated macrophages (M1). The change in macrophage phenotype by HA-PEI/miR-223 NPs could suppress the inflammation in peritoneal macrophages induced by LPS as evidenced by a significant decrease in pro-inflammatory cytokine levels TNF-α, IL-1β and IL-6, compared to LPS-stimulated peritoneal macrophages without treatment. The results demonstrated that miR-223-encapsulated HA-PEI NPs modulated macrophage polarity toward an anti-inflammatory M2 phenotype, which has potential for the treatment of inflammatory diseases.

Reprogramming of macrophages--new opportunities for therapeutic targeting

Macrophages are key players of tissue homeostasis and are cells involved in all major human diseases including infections, tumors, western life-style associated diseases and even neurodegenerative diseases. Therefore, specifically targeting macrophages seems to be an attractive therapeutic approach, yet such strategies have not been successfully translated to the clinic. An important hallmark of macrophages is their astounding plasticity and their capacity to integrate microenvironmental signals to perform distinct biological functions. Understanding the cellular programming of macrophages during such events will be a fundamental pre-requisite to develop targeted therapeutic approaches in human diseases. Here, I highlight recent findings of how macrophage activation is regulated and how one can envision much more specific approaches of targeting macrophages.

Nano- and micro-based inhaled drug delivery systems for targeting alveolar macrophages

INTRODUCTION

Macrophages are the most versatile cells in the hematopoietic system and are strategically distributed in tissues to fight pathogens or other foreign particles. In the lung, however, for intracellular infections such as tuberculosis, pneumonia and aspergillosis, bacteria and fungi utilize the alveolar macrophage as a breeding ground. This has become a challenge for the treatment of these infections, as most drugs do not effectively reach the macrophages at therapeutic levels. Alveolar macrophages also play an important role to initiative adaptive immunity toward combating inflammation and cancer in the lung.

AREAS COVERED

This review focuses on the development of micro- and nanotechnology-based drug delivery systems to target alveolar macrophages in association with intracellular infections, cancer and lung inflammation. Aspects of nanoparticle and micron-sized particle engineering through exploitation of particles' physicochemical characteristics such as particle size, surface charge and geometry of particles are discussed. In addition, the application of nanocarriers such as liposomes, polymeric nanoparticles and dendrimers are covered with respect to macrophage targeting.

EXPERT OPINION

Drug delivery targeted to alveolar macrophages in the lung is becoming a reality thanks to micro- and nanotechnology breakthrough. The literature review shows that regulation of physicochemical parameters of particles could be a recipe to enhance macrophage targeting and uptake. However, there is still a need to identify more target-specific receptors in order to facilitate drug targeting. Besides that, the toxicity of nanocarriers arising from prolonged residence in the lung should be taken into consideration during formulation.

Exosomes as nanocarriers for immunotherapy of cancer and inflammatory diseases

Cell secreted exosomes (30-100nm vesicles) play a major role in intercellular communication due to their ability to transfer proteins and nucleic acids from one cell to another. Depending on the originating cell type and the cargo, exosomes can have immunosuppressive or immunostimulatory effects, which have potential application as immunotherapies for cancer and autoimmune diseases. Cellular components shed from tumor cells or antigen presenting cells (APCs), such as dendritic cells, macrophages and B cells, have been shown to be efficiently packaged in exosomes. In this review, we focus on the application of exosomes as nanocarriers and immunological agents for cancer and autoimmune immunotherapy. APC-derived exosomes demonstrate effective therapeutic efficacy for the treatment of cancer and experimental autoimmune diseases such as rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis. In addition to their intrinsic immunomodulating activity, exosomes have many advantages over conventional nanocarriers for drug and gene delivery.