Chicken biliary exosomes enhance CD4(+)T proliferation and inhibit ALV-J replication in liver

Recent Progress in Mesenchymal Stem Cell-Derived Exosomes for Skin Wound Repair

BACKGROUND

Exosomes are nanometer-sized, lipid bilayer membrane vesicles that are secreted by various cell types. Mesenchymal stem cells (MSCs) have been shown to exert therapeutic effects through the secretion of exosomes via a paracrine pathway. Functions: Recent studies have demonstrated that MSC-derived exosomes (MSC-Exos) can effectively transport various bioactive substances, including proteins, mRNAs, microRNAs, long non-coding RNAs, circular RNAs, and lipids, into target cells. This process regulates multiple aspects during wound repair, such as the inflammatory response, cell proliferation, migration, differentiation, angiogenesis, and matrix remodeling.

POTENTIAL APPLICATIONS

By promoting wound healing and inhibiting scar formation, MSC-Exos have shown great promise for clinical applications in wound repair. This review highlights the recent advances in our understanding of the role and mechanism of MSC-Exos during wound repair, providing insights into their potential use in future therapeutic strategies.

Curcumin Changed the Number, Particle Size, and miRNA Profile of Serum Exosomes in Roman Laying Hens under Heat Stress

Exosomes have the ability to transport RNA/miRNAs and possess immune modulatory functions. Heat stress, a significant limiting factor in the poultry industry, can induce oxidative stress and suppress the immune responses of laying hens. In this study, we investigated the expression profiles of serum exosomes and their miRNAs in Roman laying hens who were fed a diet with either 0 or 200 mg/kg curcumin under heat stress conditions. The numbers of exosomes were significantly higher in both the HC (heat stress) and HT (heat stress with 200 mg/kg curcumin) groups compared to the NC (control) group and NT (control with 200 mg/kg curcumin) group (p < 0.05). Additionally, we observed that the most prevalent particle diameters were 68.75 nm, 68.25 nm, 54.25 nm, and 60.25 nm in the NC, NT, HC, and HT groups, respectively. From our sRNA library analysis, we identified a total of 863 unique miRNAs; among them, we screened out for subsequent bioinformatics analysis a total of 328 gga-miRNAs(chicken miRNA from the miRbase database). The KEGG pathways that are associated with target genes which are regulated by differentially expressed miRNAs across all four groups at a p-value < 0.01 included oxidative phosphorylation, protein export, cysteine and methionine metabolism, fatty acid degradation, ubiquitin-mediated proteolysis, and cardiac muscle contraction. The above findings suggest that curcumin could mitigate heat-induced effects on laying hens by altering the miRNA expression profiles of serum exosomes along with related regulatory pathways.

Exosomes: Friends or Foes in Microbial Infections?

The use of new approaches is necessary to address the global issue of infections caused by drug-resistant pathogens. Antimicrobial photodynamic therapy (aPDT) is a promising approach that reduces the emergence of drug resistance, and no resistance has been reported thus far. APDT involves using a photosensitizer (PS), a light source, and oxygen. The mechanism of aPDT is that a specific wavelength of light is directed at the PS in the presence of oxygen, which activates the PS and generates reactive oxygen species (ROS), consequently causing damage to microbial cells. However, due to the PS's poor stability, low solubility in water, and limited bioavailability, it is necessary to employ drug delivery platforms to enhance the effectiveness of PS in photodynamic therapy (PDT). Exosomes are considered a desirable carrier for PS due to their specific characteristics, such as low immunogenicity, innate stability, and high ability to penetrate cells, making them a promising platform for drug delivery. Additionally, exosomes also possess antimicrobial properties, although in some cases, they may enhance microbial pathogenicity. As there are limited studies on the use of exosomes for drug delivery in microbial infections, this review aims to present significant points that can provide accurate insights.

Exosomes in pathogenesis, diagnosis, and therapy of ischemic stroke

Ischemic stroke is one of the major contributors to death and disability worldwide. Thus, there is an urgent need to develop early brain tissue perfusion therapies following acute stroke and to enhance functional recovery in stroke survivors. The morbidity, therapy, and recovery processes are highly orchestrated interactions involving the brain with other tissues. Exosomes are natural and ideal mediators of intercellular information transfer and recognized as biomarkers for disease diagnosis and prognosis. Changes in exosome contents express throughout the physiological process. Accumulating evidence demonstrates the use of exosomes in exploring unknown cellular and molecular mechanisms of intercellular communication and organ homeostasis and indicates their potential role in ischemic stroke. Inspired by the unique properties of exosomes, this review focuses on the communication, diagnosis, and therapeutic role of various derived exosomes, and their development and challenges for the treatment of cerebral ischemic stroke.

Infectious bursal disease virus replication is inhibited by avain T cell chemoattractant chemokine CCL19

Chemokine CCL19, together with its receptor CCR7, is one of the most important factors recruiting immune cells into target organ during virus infection. Our previous study has shown that CCL19 played a vital role in the process of T cell trafficking into bursae during bursal disease virus (IBDV) infection. In this study, we hypothesized that CCL19 could exert direct influences on IBDV replication other than recruiting immune cells. A eukaryotic expression vector of pEGFP-N1/CCL19 was successfully constructed and identified by PCR, double enzymes digestion, and sequencing. Different concentrations of pEGFP-N1/CCL19 plasmids were transfected into DF1 cells and CCL19 protein was highly expressed. Then, DF1 cells were infected with IBDV B87 strain post-transfection. Based on PCR and Western blot results, CCL19 could obviously decrease the gene levels of VP1 and VP2 and the protein levels of VP2 and VP3. When CCL19 was knocked down, the gene levels of VP1 and VP2 were significantly upregulated. Moreover, indirect immunostaining revealed that the IBDV content was largely decreased after CCL19 overexpression. Additionally, CCL19 inhibitory effects might rely on activation of the JNK signal pathway. Taken together, chemokine CCL19 directly blocks IBDV replication in DF1 cells, indicating that CCL19 could play crucial functions other than recruiting T cells during the pathogenesis of IBDV.

Recombinant invasive Lactobacillus plantarum expressing the J subgroup avian leukosis virus Gp85 protein induces protection against avian leukosis in chickens

Avian leukosis, caused by avian leukosis virus (ALV), is an infectious tumor disease and severely hinders the development of the poultry industry. The use of Lactobacillus plantarum (L. plantarum) could effectively alleviate viremia in the early period of J subgroup ALV (ALV-J) infection. In this study, an invasive L. plantarum NC8 expressing Gp85 protein of ALV-J was constructed. After chickens were orally administered the recombinant invasive NC8, the levels of expression of CD4⁺ and CD8⁺ T lymphocytes in peripheral blood and spleen by flow cytometry and the proliferation ability of splenocytes by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were examined, and the contents of cytokines, the anti-ALV-J antibody in serum, and mucosal antibody sIgA in intestinal lavage fluid were detected by enzyme-linked immunosorbent assay (ELISA). The immunoprotective efficiency was evaluated by monitoring the infection rate, the percent of cloacal swabs and survival, body weight gain, the organ indexes, and relative virus loads after challenge with ALV-J. The results showed that the recombinant invasive strain (FnBPA-gp85) could promote the expression levels of the CD8⁺T cells in peripheral blood and spleen, the proliferation of splenocytes, the secretions of cytokines interleukin 2 (IL-2) and γ-interferon (IFN-γ), and the production of IgG and sIgA compared with the PBS and FnBPA control groups in chickens. The FnBPA-gp85 group was exhibited the highest immune protection against ALV-J infection. The above results indicated that the recombinant invasive NC8 could promote the cellular immunity, humoral immunity, and mucosal immunity responses in chicken and provide a new method for exploring the live vaccine against ALV-J.Key points• The FnBPA-gp85 strain could enhance cellular immunity response.• The FnBPA-gp85 strain could improve the immune protection against ALV-J infection.

Characterization of the Role of Extracellular Vesicles Released from Chicken Tracheal Cells in the Antiviral Responses against Avian Influenza Virus

During viral respiratory infections, the innate antiviral response engages a complex network of cells and coordinates the secretion of key antiviral factors, such as cytokines, which requires high levels of regulation and communication. Extracellular vesicles (EVs) are particles released from cells that contain an array of biomolecules, including lipids, proteins, and RNAs. The contents of EVs can be influenced by viral infections and may play a role in the regulation of antiviral responses. We hypothesized that the contents of EVs released from chicken tracheal cells are influenced by viral infection and that these EVs regulate the function of other immune cells, such as macrophages. To this end, we characterized the protein profile of EVs during avian influenza virus (AIV) infection and evaluated the impact of EV stimulation on chicken macrophage functions. A total of 140 differentially expressed proteins were identified upon stimulation with various stimuli. These proteins were shown to be involved in immune responses and cell signaling pathways. In addition, we demonstrated that EVs can activate macrophages. These results suggest that EVs play a role in the induction and modulation of antiviral responses during viral respiratory infections in chickens.

Investigating the growth performance, meat quality, immune function and proteomic profiles of plasmal exosomes in Lactobacillus plantarum-treated broilers with immunological stress

Exosomes are extracellular membranous nanovesicles that carry functional molecules to mediate cell-to-cell communication. To date, whether probiotics improve the immune function of broilers by plasmal exosome cargo is unclear. In this study, 300 broilers were allocated to three treatments: control diet (CON group), control diet + dexamethasone injection (DEX group), and control diet containing 1 × 10⁸ cfu g^-1 P8 + DEX injection (P8 + DEX group). The growth performance, meat quality and immune function of plasma and jejunal mucosa were detected. Exosomes were isolated from the plasma and characterized. Then, the exosome protein profile was determined by proteomic analysis. Correlation analyses between the exosomal proteins and growth performance, meat quality, immune function were performed. Lastly, the related protein levels were verified by multiple reaction monitoring (MRM). Results showed that P8 treatment increased the growth performance, meat quality and immune function of DEX-induced broilers with immunological stress. Moreover, the average diameters, cup-shaped morphology and expressed exosomal proteins confirmed that the isolated extracellular vesicles were exosomes. A total of 784 proteins were identified in the exosomes; among which, 126 differentially expressed proteins (DEPs) were found between the DEX and CON groups and 102 DEPs were found between the P8 + DEX and DEX groups. Gene ontology analysis indicated that DEPs between the DEX and CON groups are mainly involved in the metabolic process, cellular anatomical entity, cytoplasm, etc. DEPs between the P8 + DEX and DEX groups are mainly involved in the multicellular organismal process, response to stimulus, cytoplasm, etc. Pathway analysis revealed that most of the DEPs between the DEX and CON groups participated in the ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton, etc. Most of the DEPs between the P8 + DEX and DEX groups participated in the ErbB and PPAR signaling pathways. Moreover, many DEPs were correlated with the altered parameters of growth performance, meat quality and immunity in P8-treated broilers. MRM further revealed that the upregulated FABP6 and EPCAM in the DEX group were decreased by P8 + DEX treatment, and the downregulated C1QTNF3 in the DEX group was increased by P8 + DEX treatment. In conclusion, our findings demonstrated that P8 may promote the immune function, growth performance and meat quality of broilers with immunological stress by regulating the plasma exosomal proteins, especially the proteins of FABP6, EPCAM and C1QTNF3 and the pathway of PPAR (ILK/FABP6).

Analyzing master regulators and scRNA-seq of COVID-19 patients reveals an underlying anti-SARS-CoV-2 mechanism of ZNF proteins

Studies have demonstrated that both mortality and severe illness rates exist significant difference in different gender COVID-19 patients, but the reasons are still very mysterious to date. Here, we firstly find that the survival outcome of female patients is better to male patients through analyzing the 3044 COVID-19 cases. Secondly, we identify many important master regulators [e.g. STAT1/STAT2 and zinc finger (ZNF) proteins], in particular female patients can express more ZNF proteins and stronger transcriptional activities than male patients in response to SARS-CoV-2 infection. Thirdly, we discover that ZNF protein activity is significantly negative correlation with the SARS-CoV-2 load of COVID-19 patients, and ZNF proteins as transcription factors can also activate their target genes to participate in anti-SARS-CoV-2 infection. Fourthly, we demonstrate that ZNF protein activity is positive correlation with the abundance of multiple immune cells of COVID-19 patients, implying that the highly ZNF protein activity might promote the abundance and the antiviral activity of multiple immune cells to effectively suppress SARS-CoV-2 infection. Taken together, our study proposes an underlying anti-SARS-COV-2 role of ZNF proteins, and differences in the amount and activity of ZNF proteins might be responsible for the distinct prognosis of different gender COVID-19 patients.

Roles of Bile-Derived Exosomes in Hepatobiliary Disease

Exosomes are vesicles with a diameter of 30-150 nm produced by living cells and secreted into the extracellular matrix. Exosomes mediate cellular communication by carrying active molecules, such as nucleic acids, proteins, and liposomes. Although exosomes are found in various body fluids, little is known about bile-derived exosomes. This review is the first to summarize the methods of bile storage and isolation of biliary exosomes, highlighting the roles of bile-derived exosomes, especially exosomal noncoding RNAs, in physiological and disease states and discussing their potential clinical applications.

Exosomes Transmit Viral Genetic Information and Immune Signals may cause Immunosuppression and Immune Tolerance in ALV-J Infected HD11 cells

Avian leukosis virus (ALV) is oncogenic retrovirus that not only causes immunosuppression but also enhances the host's susceptibility to secondary infection. Exosomes play vital role in the signal transduction cascades that occur in response to viral infection. We want to explore the function of exosomes in the spread of ALV and the body's subsequent immunological response. RNA-sequencing and the isobaric tags for relative and absolute quantitation (iTRAQ) method were used to detect differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) in exosomes secreted by macrophage cells in response to injection with ALV subgroup J (ALV-J). RNA-sequencing identified 513 DEGs in infected cells, with specific differential regulation in mRNA involved in tight junction signaling, TNF signaling, salmonella infection response, and immune response, among other important cellular processes. Differential regulation was observed in 843 lncRNAs, with particular enrichment in those lncRNA targets involved in Rap1 signaling, HTLV-I infection, tight junction signaling, and other signaling pathways. A total of 50 DEPs were identified in the infected cells by iTRAQ. The proteins enriched are involved in immune response, antigen processing, the formation of both MHC protein and myosin complexes, and transport. Combined analysis of the transcriptome and proteome revealed that there were 337 correlations between RNA and protein enrichment, five of which were significant. Pathways that were enriched on both the RNA and protein levels were involved in pathways in cancer, PI3K-Akt signaling pathway, Endocytosis, Epstein-Barr virus infection. These data show that exosomes are transmitters of intercellular signaling in response to viral infection. Exosomes can carry both viral nucleic acids and proteins, making it possible for exosomes to be involved in the viral infection of other cells and the transmission of immune signals between cells. Our sequencing results confirme previous studies on exosomes and further find exosomes may cause immunosuppression and immune tolerance.

Cholangiocyte-Derived Exosomal lncRNA H19 Promotes Macrophage Activation and Hepatic Inflammation under Cholestatic Conditions

Activation of hepatic macrophages represents the critical driving force to promote cholestatic liver injury. Exosomes, as important small extracellular vesicles released by almost all types of cells, contribute to intercellular communication. We previously reported that cholangiocyte-derived exosomal long noncoding RNA (lncRNA) H19 plays a vital role in disrupting bile acid homeostasis in hepatocytes and promoting the activation of hepatic stellate cells (HSCs). Exosomal H19 derived from cholangiocytes was rapidly taken up by Kupffer cells. However, the mechanistic links between exosomal lncRNA H19 and macrophage-driven inflammation in cholestasis remain unclear. Here, we reported that the hepatic H19 level was closely correlated with macrophage activation and hepatic fibrosis in both Mdr2-/- and bile duct ligation (BDL) cholestatic mouse models, as well as in human primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) patients. Exosomal H19 significantly induced the expression and secretion of chemokine (C-C motif) ligand 2 (CCL-2) and interleukin 6 (IL-6) in Kupffer cells. H19-enriched exosomes enhanced the activation M1 polarization of Kupffer cells and promoted the recruitment and differentiation of bone marrow-derived macrophages, which were inhibited by a CCL-2 pharmacological inhibitor. In conclusion, Cholangiocyte-derived exosomal H19 played a critical role in macrophage activation, differentiation, and chemotaxis through CCL-2/CCR-2 signaling pathways, which represent a therapeutic target for cholestatic liver diseases.

Cellular Evidence and Source of Exosomes in the Biliary System of the Chinese Soft-Shelled Turtle, Pelodiscus sinensis

Exosomes are extracellular vesicles with a size of 40–150 nm that are released from a multitude of cell types and are present in biological fluids, which are particularly rich in membrane proteins. These vesicles are present in the bile, where they function as a special regulator of the digestive system; however, their source and characteristics in normal gallbladders have never been discovered. Bile, liver, and gallbladder were obtained from healthy turtles after starvation treatment. Biliary exosomes were extracted and their morphology, particle sizes, and specific proteins were characterized by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) staining, and Western blotting. Furthermore, immunohistochemistry and TEM were used to investigate the distribution of exosomes in both liver and gallbladder. Biliary exosomes had a round or oval shape with apparent bilayer membranes. Biliary exosomes were uniform in size, with a range from 40 to 180 nm in diameter. Immunohistochemistry showed that the CD63 exosome marker was positive and primarily distributed in the hepatocyte junction, while the free surface of gallbladder tested negative. In addition, exosomes were present in bile but absent on the apical free surface of gallbladder. This study provides direct evidences that biliary exosomes are secreted by hepatocytes into bile canaliculus and flow with bile into the gallbladder. The source and the isolated protocol of biliary exosomes may provide technical support and a theoretical basis for the exploration of potential antiviral or anti-inflammatory properties of biliary exosomes.

Progress on chicken T cell immunity to viruses

Avian virus infection remains one of the most important threats to the poultry industry. Pathogens such as avian influenza virus (AIV), avian infectious bronchitis virus (IBV), and infectious bursal disease virus (IBDV) are normally controlled by antibodies specific for surface proteins and cellular immune responses. However, standard vaccines aimed at inducing neutralizing antibodies must be administered annually and can be rendered ineffective because immune-selective pressure results in the continuous mutation of viral surface proteins of different strains circulating from year to year. Chicken T cells have been shown to play a crucial role in fighting virus infection, offering lasting and cross-strain protection, and offer the potential for developing universal vaccines. This review provides an overview of our current knowledge of chicken T cell immunity to viruses. More importantly, we point out the limitations and barriers of current research and a potential direction for future studies.

Reticuloendotheliosis virus and avian leukosis virus subgroup J synergistically increase the accumulation of exosomal miRNAs

BACKGROUND

Co-infection with avian leukosis virus subgroup J and reticuloendotheliosis virus induces synergistic pathogenic effects and increases mortality. However, the role of exosomal miRNAs in the molecular mechanism of the synergistic infection of the two viruses remains unknown.

RESULTS

In this study, exosomal RNAs from CEF cells infected with ALV-J, REV or both at the optimal synergistic infection time were analysed by Illumina RNA deep sequencing. A total of 54 (23 upregulated and 31 downregulated) and 16 (7 upregulated and 9 downregulated) miRNAs were identified by comparing co-infection with two viruses, single-infected ALV-J and REV, respectively. Moreover, five key miRNAs, including miR-184-3p, miR-146a-3p, miR-146a-5p, miR-3538 and miR-155, were validated in both exosomes and CEF cells by qRT-PCR. GO annotation and KEGG pathway analysis of the miRNA target genes showed that the five differentially expressed miRNAs participated in virus-vector interaction, oxidative phosphorylation, energy metabolism and cell growth.

CONCLUSIONS

We demonstrated that REV and ALV-J synergistically increased the accumulation of exosomal miRNAs, which sheds light on the synergistic molecular mechanism of ALV-J and REV.

Exosomes in Pathogen Infections: A Bridge to Deliver Molecules and Link Functions

Exosomes are extracellular vesicles derived from cell endocytosis which act as transmitters between cells. They are composed of proteins, lipids, and RNAs through which they participate in cellular crosstalk. Consequently, they play an important role in health and disease. Our view is that exosomes exert a bidirectional regulatory effect on pathogen infections by delivering their content. First, exosomes containing proteins and RNAs derived from pathogens can promote infections in three ways: (1) mediating further infection by transmitting pathogen-related molecules; (2) participating in the immune escape of pathogens; and (3) inhibiting immune responses by favoring immune cell apoptosis. Second, exosomes play anti-infection roles through: (1) inhibiting pathogen proliferation and infection directly; (2) inducing immune responses such as those related to the function of monocyte-macrophages, NK cells, T cells, and B cells. We believe that exosomes act as “bridges” during pathogen infections through the mechanisms mentioned above. The purpose of this review is to describe present findings regarding exosomes and pathogen infections, and highlight their enormous potential in clinical diagnosis and treatment. We discuss two opposite aspects: infection and anti-infection, and we hypothesize a balance between them. At the same time, we elaborate on the role of exosomes in immune regulation.

Decoding the Role of Extracellular Vesicles in Liver Diseases

Cell-to-cell communication is a fascinating process that is essential for maintaining tissue and whole-body homeostasis. Extracellular vesicles (EVs) are cell-derived membrane-bound nanoparticles that are a means of communication between cells. Accumulating evidence indicates that EVs can render either beneficial or harmful outcomes, depending on the specific cargos (e.g. proteins, lipids, RNAs) transferred between cells. EVs also have great value as diagnostic and prognostic markers of disease because they are present in a variety of biological fluids and carry bioactive molecules from their cells or tissues of origin. Liver cells can both release and receive EVs derived from other cells and emerging evidence indicates that liver EVs play important roles in the pathogenesis of various liver diseases, including liver cancer, viral hepatitis, non-alcoholic fatty liver disease, and alcoholic liver disease. This review provides an overview of the biogenesis and secretion of EVs and summarizes the most recent advances in understanding the role of EVs in liver physiology and diseases. Additionally, we discuss potential applications of liver EVs as biomarkers and in therapeutic approaches to treat liver diseases.

Extracellular vesicles in liver disease and potential as biomarkers and therapeutic targets

Extracellular vesicles (EVs) are membranous vesicles originating from different cells in the liver. The pathophysiological role of EVs is increasingly recognized in liver diseases, including alcoholic liver disease, NAFLD, viral hepatitis and hepatocellular carcinoma. EVs, via their cargo, can provide communication between different cell types in the liver and between organs. EVs are explored as biomarkers of disease and could also represent therapeutic targets and vehicles for treatment delivery. Here, we review advances in understanding the role of EVs in liver diseases and discuss their utility in biomarker discovery and therapeutics.

Immunity to Avian Leukosis Virus: Where Are We Now and What Should We Do?

Avian leukosis virus (ALV) is an avian oncogenic retrovirus causing enormous economic losses in the global poultry industry. Although ALV-related research has lasted for more than a century, there are no vaccines to protect chickens from ALV infection. The interaction between chickens and ALV remains not fully understood especially with regard to the host immunity. The current review provides an overview of our current knowledge of innate and adaptive immunity induced by ALV infection. More importantly, we have pointed out the unknown area involved in ALV-related studies, which is worthy of our serious exploring in future.

Exosomes for Immunoregulation and Therapeutic Intervention in Cancer

Exosomes, as a subset of extracellular vesicles, function as a mode of intercellular communication and molecular transfer, and facilitate the direct extracellular transfer of proteins, lipids, and miRNAs/mRNAs/DNAs between cells. Cancers have adapted exosomes and related microvesicles as a pathway that can suppress the immune system and establish a fertile local and distant environment to support neoplastic growth, invasion, and metastasis; these tumor-derived exosomes affect immunoregulation mechanisms, including immune activation and immune suppression. Immune cell-derived exosomes can modulate the immune response in cancer, which supports the belief that these membranous vesicles are immunotherapeutic reagents. In this review, we discuss the recent advances in the cancer immunotherapy, roles of exosomes in cancer, immunoregulation of tumor-derived exosomes, and immunomodulation by immune cell-derived exosomes. The topics covered here highlight novel insights into the development of efficient exosome-based cancer vaccines for cancer therapeutic intervention.

Extracellular vesicles from infected cells: potential for direct pathogenesis

Infections that result in natural or manmade spread of lethal biological agents are a concern and require national and focused preparedness. In this manuscript, as part of an early diagnostics and pathogen treatment strategy, we have focused on extracellular vesicles (EVs) that arise following infections. Although the field of biodefense does not currently have a rich resource in EVs literature, none the less, similar pathogens belonging to the more classical emerging and non-emerging diseases have been studied in their EV/exosomal contents and function. These exosomes are formed in late endosomes and released from the cell membrane in almost every cell type in vivo. These vesicles contain proteins, RNA, and lipids from the cells they originate from and function in development, signal transduction, cell survival, and transfer of infectious material. The current review focuses on how different forms of infection exploit the exosomal pathway and how exosomes can be exploited artificially to treat infection and disease and potentially also be used as a source of vaccine. Virally-infected cells can secrete viral as well as cellular proteins and RNA in exosomes, allowing viruses to cause latent infection and spread of miRNA to nearby cells prior to a subsequent infection. In addition to virally-infected host cells, bacteria, protozoa, and fungi can all release small vesicles that contain pathogen-associated molecular patterns, regulating the neighboring uninfected cells. Examples of exosomes from both virally and bacterially infected cells point toward a re-programming network of pathways in the recipient cells. Finally, many of these exosomes contain cytokines and miRNAs that in turn can effect gene expression in the recipient cells through the classical toll-like receptor and NFκB pathway. Therefore, although exosomes do not replicate as an independent entity, they however facilitate movement of infectious material through tissues and may be the cause of many pathologies seen in infected hosts.