Cell-free Vaccine Research Articles

Melanoma extracellular vesicles inhibit tumor growth and metastasis by stimulating CD8 T cells

Tumor cell-derived extracellular vesicles (EVs) play a crucial role in mediating immune responses by carrying and presenting tumor antigens. Here, we suggested that melanoma EVs triggered cytotoxic CD8 T cell-mediated inhibition of tumor growth and metastasis. Our results indicated that immunization of mice with melanoma EVs inhibited melanoma growth and metastasis while increasing CD8 T cells and serum interferon γ (IFN-γ) in vivo. In vitro experiments showed that melanoma EV stimulates dendritic cells (DCs) maturation, and mature dendritic cells induce T lymphocyte activation. Thus, tumor cell-derived EVs can generate anti-tumor immunity in a prophylactic setting and may be potential candidates for cell-free tumor vaccines.

In Silico Design of a Trans-Amplifying RNA-Based Vaccine against SARS-CoV-2 Structural Proteins.

Nucleic acid-based vaccines allow scalable, rapid, and cell-free vaccine production in response to an emerging disease such as the current COVID-19 pandemic. Here, we objected to the design of a multiepitope mRNA vaccine against the structural proteins of SARS-CoV-2. Through an immunoinformatic approach, promising epitopes were predicted for the spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins. Fragments rich in overlapping epitopes were selected based on binding affinities with HLA classes I and II for the specific presentation to B and T lymphocytes. Two constructs were designed by fusing the fragments in different arrangements via GG linkers. Construct 1 showed better structural properties and interactions with toll-like receptor 2 (TLR-2), TLR-3, and TLR-4 during molecular docking and dynamic simulation. A 50S ribosomal L7/L12 adjuvant was added to its N-terminus to improve stability and immunogenicity. The final RNA sequence was used to design a trans-amplifying RNA (taRNA) vaccine in a split-vector system. It consists of two molecules: a nonreplicating RNA encoding a trans-acting replicase to amplify the second one, a trans-replicon (TR) RNA encoding the vaccine protein. Overall, the immune response simulation detected that activated B and T lymphocytes and increased memory cell formation. Macrophages and dendritic cells proliferated continuously, and IFN-γ and cytokines like IL-2 were released highly.

Landscape of tumor and immune system cells-derived exosomes in lung cancer: mediators of antitumor immunity regulation.

The immune system plays a critical role in cancer, including lung cancer, which is the leading cause of cancer-related deaths worldwide. Immunotherapy, particularly immune checkpoint blockade, has revolutionized the treatment of lung cancer, but a large subset of patients either do not respond or develop resistance. Exosomes, essential mediators of cell-to-cell communication, exert a profound influence on the tumor microenvironment and the interplay between cancer and the immune system. This review focuses on the role of tumor-derived exosomes and immune cells-derived exosomes in the crosstalk between these cell types, influencing the initiation and progression of lung cancer. Depending on their cell of origin and microenvironment, exosomes can contain immunosuppressive or immunostimulatory molecules that can either promote or inhibit tumor growth, thus playing a dual role in the disease. Furthermore, the use of exosomes in lung cancer immunotherapy is discussed. Their potential applications as cell-free vaccines and drug delivery systems make them an attractive option for lung cancer treatment. Additionally, exosomal proteins and RNAs emerge as promising biomarkers that could be employed for the prediction, diagnosis, prognosis and monitoring of the disease. In summary, this review assesses the relationship between exosomes, lung cancer, and the immune system, shedding light on their potential clinical applications and future perspectives.

Dendritic Cell-Derived Exosomes in Cancer Immunotherapy.

Exosomes are nanoscale vesicles released by diverse types of cells for complex intercellular communication. Numerous studies have shown that exosomes can regulate the body's immune response to tumor cells and interfere with the tumor microenvironment (TME). In clinical trials on dendritic cell (DC)-based antitumor vaccines, no satisfactory results have been achieved. However, recent studies suggested that DC-derived exosomes (DEXs) may be superior to DC-based antitumor vaccines in avoiding tumor cell-mediated immunosuppression. DEXs contain multiple DC-derived surface markers that capture tumor-associated antigens (TAAs) and promote immune cell-dependent tumor rejection. These findings indicate the necessity of the further development and improvement of DEX-based cell-free vaccines to complement chemotherapy, radiotherapy, and other immunotherapies. In this review, we highlighted the recent progress of DEXs in cancer immunotherapy, particularly by concentrating on landmark studies and the biological characterization of DEXs, and we summarized their important role in the tumor immune microenvironment (TIME) and clinical application in targeted cancer immunotherapy. This review could enhance comprehension of advances in cancer immunotherapy and contribute to the elucidation of how DEXs regulate the TIME, thereby providing a reference for utilizing DEX-based vaccines in clinical practice.

Exosomes: Nomenclature, Isolation, and Biological Roles in Liver Diseases.

The biogenesis and biological roles of extracellular vesicles (EVs) in the progression of liver diseases have attracted considerable attention in recent years. EVs are membrane-bound nanosized vesicles found in different types of body fluids and contain various bioactive materials, including proteins, lipids, nucleic acids, and mitochondrial DNA. Based on their origin and biogenesis, EVs can be classified as apoptotic bodies, microvesicles, and exosomes. Among these, exosomes are the smallest EVs (30-150 nm in diameter), which play a significant role in cell-to-cell communication and epigenetic regulation. Moreover, exosomal content analysis can reveal the functional state of the parental cell. Therefore, exosomes can be applied to various purposes, including disease diagnosis and treatment, drug delivery, cell-free vaccines, and regenerative medicine. However, exosome-related research faces two major limitations: isolation of exosomes with high yield and purity and distinction of exosomes from other EVs (especially microvesicles). No standardized exosome isolation method has been established to date; however, various exosome isolation strategies have been proposed to investigate their biological roles. Exosome-mediated intercellular communications are known to be involved in alcoholic liver disease and nonalcoholic fatty liver disease development. Damaged hepatocytes or nonparenchymal cells release large numbers of exosomes that promote the progression of inflammation and fibrogenesis through interactions with neighboring cells. Exosomes are expected to provide insight on the progression of liver disease. Here, we review the biogenesis of exosomes, exosome isolation techniques, and biological roles of exosomes in alcoholic liver disease and nonalcoholic fatty liver disease.

Analysis of a Serological Study of Pertussis among Children and Adolescents in the Republic of Kazakhstan

Relevance. In 2018 over 151 000 cases of whooping cough were reported worldwide. In the Republic of Kazakhstan the incidence of whooping cough has always remained relevant. The incidence is recorded mainly among children under 14 years of age, whose share is 96–100% of the total incidence in certain years. It should also be noted that 82,9–96% of sick people are not vaccinated against whooping cough. Aims. Assessment of the duration of protection after vaccination against pertussis infection in Kazakhstan using antibodies against pertussis toxin (PT) and (IgA and IgG) as a specific marker of pertussis infection or vaccination in children and adolescents in the cities of the Republic of Kazakhstan: Aktobe, Karaganda, Taldykorgan, Shymkent for evaluation appropriate age for booster vaccination. Materials and methods. For the study included medical organizations in the cities of Aktobe, Karaganda, Taldykorgan, Shymkent. Participants aged 10–14 years who were hospitalized in children's hospitals and 15–18 years old who visited polyclinics were invited to participate in the study. Each city has 1 children's hospital (4 in total) and 2 polyclinics (8 in total). A total of 520 people of different age groups participated. Study period: February 2021 – October 2021. Inclusion criteria were such aspects as: age from 10 years to 18 years 11 months 29 days, informed consent obtained from parents or guardian(s) and patient consent, enrollment after visiting the clinic, the presence of documented evidence of immune status. An association between two qualitative variables is considered statistically significant if the p-value calculated using the Chi-squared test is less than 0.05. Results. Among 520 participants aged 10–14 years – 200 (38.5%) and 15–18 years – 320 (61.5%), including boys – 284 (54.6%), girls – 236 (45.4%). The largest number of study participants was aged 15, 16 and 17 years, 10 participants (1.9%) had periods of prolonged coughing in the past 6 months. The first, second and third pertussis vaccines were received by 100% of children. The first and second vaccine for all children was the Adsorbed Diphtheria-Tetanus-Pertussis Vaccine (DPT). The third vaccine for 519 children was also DPT, for one child – AbDPT, due to the transition to a cell-free vaccine from the second half of 2013. The additional vaccine scheduled at 18 months of age was given to 519 participants (99.8%), of which 517 children (99.6%) received DPT and two children (0.4%) DPT. Just over half of the children (276 or 53.1%) also received the whooping cough vaccine at age 6. In biological blood samples of 17 participants (3.3%). antibodies of the IgA class were detected in 245 samples (47.1%) – antibodies of the IgG class. Of the 17 participants with IgA antibodies, 15 also tested positive for IgG. In total antibodies of the IgA and IgG classes were detected in 247 participants which amounted to 47.5%. Conclusions. This study showed the duration of protection after pertussis vaccination in Kazakhstan among different age groups. In total, antibodies of the IgA and IgG classes were detected in 247 participants out of 520 which amounted to 47.5%. IgA antibodies were detected in biological blood samples in 17 participants (3.3%), IgG class antibodies in 245 samples (47.1%). The prevalence of IgA antibodies was statistically significantly higher among older children and among children who had respiratory symptoms in the 6 months prior to the study. The prevalence of IgG antibodies was statistically significantly higher among children vaccinated against whooping cough at the age of 6 years (47.1%) and at the age of 10–14 years (56.2%) than in the age group of 15–18 years (43.8%) and also significantly higher among those, who share a bedroom with other family members compared to children living in separate rooms. Thus an increase in whooping cough and a decrease in protective vaccine immunity among older age groups can be stated which raises concerns about transmission of the infection in the home to vulnerable children and the need to strengthen vaccination strategies.

Dendritic Cell-Derived Artificial Microvesicles Inhibit RLS40 Lymphosarcoma Growth in Mice via Stimulation of Th1/Th17 Immune Response.

Cell-free antitumor vaccines represent a promising approach to immunotherapy of cancer. Here, we compare the antitumor potential of cell-free vaccines based on microvesicles derived from dendritic cells (DCs) with DC- and cationic-liposome-based vaccines using a murine model of drug-resistant lymphosarcoma RLS40 in vivo. The vaccines were the following: microvesicle vaccines-cytochalasin B-induced membrane vesicles (CIMVs) obtained from DCs loaded with total tumor RNA using cholesterol/spermine-containing cationic liposomes L or mannosylated liposomes ML; DC vaccines-murine DCs loaded with total tumor-derived RNA using the same liposomes; and liposomal vaccines-lipoplexes of total tumor-derived RNA with liposomes L or ML. Being non-hepatotoxic, CIMV- and DC-based vaccines administered subcutaneously exhibited comparable potential to stimulate highly efficient antitumor CTLs in vivo, whereas liposomal vaccines were 25% weaker CTL inducers. Nevertheless, the antitumor efficiencies of the different types of the vaccines were similar: sizes of tumor nodes and the number of liver metastases were significantly decreased, regardless of the vaccine type. Notably, the booster vaccination did not improve the overall antitumor efficacy of the vaccines under the study. CIMV- and DC- based vaccines more efficiently than liposome-based ones decreased mitotic activity of tumor cells and induced their apoptosis, stimulated accumulation of neutrophil inflammatory infiltration in tumor tissue, and had a more pronounced immunomodulatory activity toward the spleen and thymus. Administration of CIMV-, DC-, and liposome-based vaccines resulted in activation of Th1/Th17 cells as well as the induction of positive immune checkpoint 4-1BBL and downregulation of suppressive immune checkpoints in a raw PD-1 >>> TIGIT > CTLA4 > TIM3. We demonstrated that cell-free CIMV-based vaccines exhibited superior antitumor and antimetastatic activity in a tumor model in vivo. The obtained results can be considered as the basis for developing novel strategies for oncoimmunotherapy.

Immunotheranostic microbubbles (iMBs) - a modular platform for dendritic cell vaccine delivery applied to breast cancer immunotherapy

BackgroundTherapeutic strategies engaging the immune system against malignant cells have revolutionized the field of oncology. Proficiency of dendritic cells (DCs) for antigen presentation and immune response has spurred interest on DC-based vaccines for anti-cancer therapy. However, despite favorable safety profiles in patients, current DC-vaccines have not yet presented significant outcome due to technical barriers in active DC delivery, tumor progression, and immune dysfunction. To maximize the therapeutic response, we present here a unique cell-free DC-based vaccine capable of lymphoid organ targeting and eliciting T-cell-mediated anti-tumor effect.MethodsWe developed this novel immunotheranostic platform using plasma membranes derived from activated DCs incorporated into ultrasound contrast microbubbles (MBs), thereby offering real-time visualization of MBs’ trafficking and homing in vivo. Human PBMC-derived DCs were cultured ex vivo for controlled maturation and activation using cell membrane antigens from breast cancer cells. Following DC membrane isolation, immunotheranostic microbubbles, called DC-iMBs, were formed for triple negative breast cancer treatment in a mouse model harboring a human reconstituted immune system.ResultsOur results demonstrated that DC-iMBs can accumulate in lymphoid organs and induce anti-tumor immune response, which significantly reduced tumor growth via apoptosis while increasing survival length of the treated animals. The phenotypic changes in immune cell populations upon DC-iMBs delivery further confirmed the T-cell-mediated anti-tumor effect.ConclusionThese early findings strongly support the potential of DC-iMBs as a novel immunotherapeutic cell-free vaccine for anti-cancer therapy.

Neoantigen-based cancer vaccination using chimeric RNA-loaded dendritic cell-derived extracellular vesicles.

Cancer vaccines critically rely on the availability of targetable immunogenic cancer‐specific neoepitopes. However, mutation‐based immunogenic neoantigens are rare or even non‐existent in subgroups of cancer types. To address this issue, we exploited a cancer‐specific aberrant transcription‐induced chimeric RNA, designated A‐Pas chiRNA, as a possible source of clinically relevant and targetable neoantigens. A‐Pas chiRNA encodes a recently discovered cancer‐specific chimeric protein that comprises full‐length astrotactin‐2 (ASTN2) C‐terminally fused in‐frame to the antisense sequence of the 18th intron of pregnancy‐associated plasma protein‐A (PAPPA). We used extracellular vesicles (EVs) from A‐Pas chiRNA‐transfected dendritic cells (DCs) to produce the cell‐free anticancer vaccine DEXA‐P. Treatment of immunocompetent cancer‐bearing mice with DEXA‐P inhibited tumour growth and prolonged animal survival. In summary, we demonstrate for the first time that cancer‐specific transcription‐induced chimeric RNAs can be exploited to produce a cell‐free cancer vaccine that induces potent CD8+ T cell‐mediated anticancer immunity. Our novel approach may be particularly useful for developing cancer vaccines to treat malignancies with low mutational burden or without mutation‐based antigens. Moreover, this cell‐free anticancer vaccine approach may offer several practical advantages over cell‐based vaccines, such as ease of scalability and genetic modifiability as well as enhanced shelf life.

Emerging Roles of Extracellular Vesicles in Pneumococcal Infections: Immunomodulators to Potential Novel Vaccine Candidates.

The Gram-positive bacterial pathogen, Streptococcus pneumoniae is a major global health threat that kills over one million people worldwide. The pneumococcus commonly colonizes the nasopharynx asymptomatically as a commensal, but is also capable of causing a wide range of life-threatening diseases such as pneumonia, meningitis and septicemia upon migration into the lower respiratory tract and spread to internal organs. Emergence of antibiotic resistant strains and non-vaccine serotypes has led to the classification of pneumococcal bacteria as a priority pathogen by the World Health Organization that needs urgent research into bacterial pathogenesis and development of novel vaccine strategies. Extracellular vesicles are spherical membrane bound structures that are released by both pathogen and host cells, and influence bacterial pathogenesis as well as the immune response. Recent studies have found that while bacterial vesicles shuttle virulence factors and toxins into host cells and regulate inflammatory responses, vesicles released from the infected host cells contain both bacterial and host proteins that are antigenic and immunomodulatory. Bacterial membrane vesicles have great potential to be developed as cell-free vaccine candidates in the future due to their immunogenicity and biostability. Host-derived vesicles isolated from patient biofluids such as blood and bronchoalveolar lavage could be used to identify potential diagnostic biomarkers as well as engineered to deliver desired payloads to specific target cells for immunotherapy. In this review, we summarize the recent developments on the role of bacterial and host vesicles in pneumococcal infections and future prospects in developing novel therapeutics and diagnostics for control of invasive pneumococcal diseases.

Plasmacytoid Dendritic Cells and Cancer Immunotherapy.

Despite largely disappointing clinical trials of dendritic cell (DC)-based vaccines, recent studies have shown that DC-mediated cross-priming plays a critical role in generating anti-tumor CD8 T cell immunity and regulating anti-tumor efficacy of immunotherapies. These new findings thus support further development and refinement of DC-based vaccines as mono-immunotherapy or combinational immunotherapies. One exciting development is recent clinical studies with naturally circulating DCs including plasmacytoid DCs (pDCs). pDC vaccines were particularly intriguing, as pDCs are generally presumed to play a negative role in regulating T cell responses in tumors. Similarly, DC-derived exosomes (DCexos) have been heralded as cell-free therapeutic cancer vaccines that are potentially superior to DC vaccines in overcoming tumor-mediated immunosuppression, although DCexo clinical trials have not led to expected clinical outcomes. Using a pDC-targeted vaccine model, we have recently reported that pDCs required type 1 conventional DCs (cDC1s) for optimal cross-priming by transferring antigens through pDC-derived exosomes (pDCexos), which also cross-prime CD8 T cells in a bystander cDC-dependent manner. Thus, pDCexos could combine the advantages of both cDC1s and pDCs as cancer vaccines to achieve better anti-tumor efficacy. In this review, we will focus on the pDC-based cancer vaccines and discuss potential clinical application of pDCexos in cancer immunotherapy.

Stalling SARS-CoV2 infection with stem cells: can regenerating perinatal tissue mesenchymal stem cells offer a multi-tiered therapeutic approach to COVID-19?

The emergence of COVID-19 has created a major health crisis across the globe. Invasion of SARS-CoV-2 into the lungs causes acute respiratory distress syndrome (ARDS) that result in the damage of lung alveolar epithelial cells. Currently, there is no standard treatment available to treat the disease and the resultant lung scarring is irreversible even after recovery. This has prompted researchers across the globe to focus on developing new therapeutics and vaccines for the treatment and prevention of COVID-19. Mesenchymal stem cells (MSCs) have emerged as an efficient drug screening platform and MSC-derived organoids has found applications in disease modeling and drug discovery. Perinatal tissue derived MSC based cell therapies have been explored in the treatment of various disease conditions including ARDS because of their enhanced regenerative and immunomodulatory properties. The multi-utility properties of MSCs have been described in this review wherein we discuss the potential use of MSC-derived lung organoids in screening of novel therapeutic compounds for COVID-19 and also in disease modeling to better understand the pathogenesis of the disease. This article also summarizes the rationale behind the development of MSC-based cell- and cell-free therapies and vaccines for COVID-19 with a focus on the current progress in this area. With the pandemic raging, an important necessity is to develop novel treatment strategies which will not only alleviate the disease symptoms but also avoid any off-target effects which could further increase post infection sequelae. Naturally occurring mesenchymal stem cells could be the magic bullet which fulfil these criteria.

Immunobiological Properties of Biofilms of Bacteria of the Genus Bordetella

Relevance. Whooping cough remains a pressing public health problem worldwide, including in countries with high vaccination rates. One of the probable causes of the ongoing epidemic process of pertussis infection is B. pertussis biofilms, which differ from plankton cultures by an altered gene expression spectrum and are highly resistant to environmental conditions, antibiotics, and immune factors.Aims. Analysis of literature data on the genetic and molecular - cellular mechanisms of biofilm formation by bacteria of the genus Bordetella, as well as approaches to the search for means aimed at suppressing the growth of biofilms and the destruction of formed biofilms in the macroorganism.Conclusions. Biofilm formation by microbes of the genus Bordetella is a complex multistage process regulated by genetic signaling systems: the Bvg AS system and the 2-nucleotide (p) ppGrp system, as well as other regulatory proteins and the polysaccharide complex. The matrix of B. pertussis biofilms consists of extracellular DNA, proteins, and a polysaccharide polymer that play an important role in the formation of biofilms in the respiratory tract and on abiotic surfaces. The genetic and molecular-cellular processes of biofilm formation and maintenance, as well as the various components of the biofilm matrix, can serve as targets for new antimicrobial drugs and more effective pertussis vaccines that will better control the entire pertussis infection cycle, including colonization, persistence, and transmission of the causative agent. One of the approaches to the development of new-generation cell-free pertussis vaccines is the identification of new biofilm-associated antigens that can induce effective cellular and humoral responses. The search for drugs that can destroy biofilms, including substances that affect the matrix and facilitate the access of antibacterial drugs to microbial cells, is promising.

Tumor-Derived Exosomes Enriched by miRNA-124 Promote Anti-tumor Immune Response in CT-26 Tumor-Bearing Mice.

Exosomes have been introduced as a new alternative delivery system for the transmission of small molecules. Tumor-derived exosomes (TEXs) not only contain tumor-associated antigens to stimulate antitumor immune responses but also act as natural carriers of microRNAs. The aim of the current study was to evaluate the efficacy of miR-124-3p-enriched TEX (TEXomiR) as cell-free vaccine in the induction of antitumor immune responses in a mouse model of colorectal cancer. Briefly, the exosomes were isolated from cultured CT-26 cell line, and modified calcium chloride method was used to deliver miR-124-3p mimic into the exosomes. We used a CT-26-induced BALB/c mouse model of colorectal cancer and analyzed the effect of TEXomiR on survival, tumor size, spleen and tumor-infiltrated lymphocytes, and splenocyte proliferation. Furthermore, intra-tumor regulatory T cells, cytotoxic activity of the splenocytes, and cytokine secretion was also evaluated to describe the anti-tumor immune response. When the tumor size reached 100 mm3, the mice were injected with TEXomiR, TEX, and/or phosphate-buffered saline (PBS) subcutaneously three times with 3-day interval, and then tumor size was monitored every 2 days. The in vitro results indicated that TEXs could efficiently deliver functional miR-124-3p mimic. The in vivo evaluation in tumor-bearing mice showed that treatment with TEXomiR can elicit a stronger anti-tumor immune response than unloaded TEX and PBS. Significant tumor growth inhibition and increased median survival time was achieved in tumor-bearing mice treated with TEXomiR. A significant decrease in CD4/CD8 and Treg/CD8 ratio in tumor tissue was demonstrated. Moreover, increased cytotoxicity and proliferation of splenocytes in the TEXomiR group compared to the TEX and PBS groups were identified. Taken together, our data demonstrated that tumor-derived exosomes efficiently deliver miR-124-3p mimic, and TEXomiR promotes anti-tumor immune responses.

Сell-free pertussis vaccine from antigens of freshly isolated strain of B. pertussis serotype 1.2.3

Aim. Development of technology for the manufacture of cell-free pertussis vaccine (CPV) from a freshly isolated strain of B. pertussis No. 211 serotype 1.2.3 and the study of its protective activity and safety in comparison with the preparation of vaccine strains. Materials and methods. Following B. pertussis strains were used: freshly isolated strain No. 211, serotype 1.2.3; vaccine strains No. 305, serotype 1.2.0, and No. 475a, serotype 1.2.3. According to the original method, a CPV was obtained from the supernatant of the liquid culture medium of B. pertussis strain No. 211 and its protective and toxic properties were studied. Results. Studies have shown that the use of enriched nutrient media for the cultivation of the strain and the increase in the duration of the the detoxification period of the protective antigen complex isolated from the culture medium are needed to obtain a CPV vaccine consisting of antigens of a freshly isolated strain. CPV obtained from the freshly isolated strain had protectivity 1.7 times higher compared to those of CPV obtained from vaccine strains, was nontoxic and had a low sensitizing properties. The results indicate that the freshly isolated strain No. 211 is a promising candidate for use in the development of pertussis vaccines.

Immunotherapy Based on Dendritic Cell-Targeted/-Derived Extracellular Vesicles-A Novel Strategy for Enhancement of the Anti-tumor Immune Response.

Dendritic cell (DC)-based anti-tumor vaccines have great potential for the treatment of cancer. To date, a large number of clinical trials involving DC-based vaccines have been conducted with a view to treating tumors of different histological origins. However, DC-based vaccines had several drawbacks, including problems with targeted delivery of tumor antigens to DCs and prolong storage of cellular vaccines. Therefore, the development of other immunotherapeutic approaches capable of enhancing the immunogenicity of existing DC-based vaccines or directly triggering anti-tumor immune responses is of great interest. Extracellular vesicles (EVs) are released by almost all types of eukaryotic cells for paracrine signaling. EVs can interact with target cells and change their functional activity by delivering different signaling molecules including mRNA, non-coding RNA, proteins, and lipids. EVs have potential benefits as natural vectors for the delivery of RNA and other therapeutic molecules targeted to DCs, T-lymphocytes, and tumor cells; therefore, EVs are a promising entity for the development of novel cell-free anti-tumor vaccines that may be a favourable alternative to DC-based vaccines. In the present review, we discuss the anti-tumor potential of EVs derived from DCs, tumors, and other cells. Methods of EV isolation are systematized, and key molecules carried by EVs that are necessary for the activation of a DC-mediated anti-tumor immune response are analyzed with a focus on the RNA component of EVs. Characteristics of anti-tumor immune responses induced by EVs in vitro and in vivo are reviewed. Finally, perspectives and challenges with the use of EVs for the development of anti-tumor cell-free vaccines are considered.

Post-Vaccination Immunity to Pertussis in Children of Lipetsk, New Management Capabilitiesto Infection

Relevance. In the structure of the incidence of controlled infections in the Russian Federation, whooping cough takes one of the leading places, and in 2018 there is a two-fold increase in the incidence compared with 2017. The aim. Determination of the level of postvaccination immunity to pertussis infection in children of Lipetsk aged 3 to 10 years and assessment of the safety of booster vaccination with a combination vaccine against diphtheria and tetanus with acellular pertussis. Materials and methods . Analysis of the incidence of pertussis and the quality of vaccine prevention according to planned seromonitoring in Lipetsk (2017). 100 patients were vaccinated with a booster dose of Ada с el. The study tested reactogenicity and safety of the vaccine. Results. There is a relationship between the epidemic process of whooping cough and the short duration of post-vaccination immunity. Epidemiology of whooping cough dictates the need to change the tactics of vaccination, the introduction of repeated revaccination of children and adults using cell-free vaccines. Conclusions The data obtained confirm the safety and good tolerability of the Adacel vaccine in clinical practice.

MicroRNA modified tumor-derived exosomes as novel tools for maturation of dendritic cells.

Tumor-derived exosomes (TEX) are known by their immune suppression effects as well as initiation mediators in cancer progression and metastasis. Meanwhile, they are appropriate sources to induce immunity against tumor cells, as consist of tumor specific and associated antigens. The aim of the current study is modifying TEX with microRNA miR-155, miR-142, and let-7i, to enhance their immune stimulation ability and induce potent dendritic cells (DC). For this, exosomes were isolated from mouse mammalian breast cancer cell line; 4T1, and subjected to miR-155, miR-142, and let-7i by electroporation. Immature DCs were generated from mouse bone marrow in the presence of interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF). To mature DCs, lipopolysaccharide (LPS), TEX, and modified TEX were used. The expression level of miRNAs and their target genes (IL-6, IL-17, IL-1b, TGFβ, SOCS1, KLRK1, IFNγ, and TLR4) was determined. TEX were nanovesicles with spheroid morphology which expressed CD81, CD63, and TSG101, as exosome markers, at protein level. MHCII, CD80, and CD40 as maturation markers were assessed by flow cytometry. Overexpression of miRNAs were confirmed in exosomes and mDCs. Up and downregulation of target genes confirmed the gene network in DC maturation. We found that Let-7i could efficiently induce the DC maturation, as well as miR-142 and miR-155 have enhancing effects. These findings reveal that the modified TEX would be a hopeful cell-free vaccine for the cancer treatment.

Mechanisms by Which Dendritic Cells Present Tumor Microparticle Antigens to CD8+ T Cells.

Tumor cell-derived microparticles (T-MP) contain tumor antigen profiles as well as innate signals, endowing them with vaccine potential; however, the precise mechanism by which DCs present T-MP antigens to T cells remains unclear. Here, we show that T-MPs activate a lysosomal pathway that is required for DCs presenting tumor antigens of T-MPs. DCs endocytose T-MPs to lysosomes, where T-MPs increase lysosomal pH from 5.0 to a peak of 8.5 via NOX2-catalyzed reactive oxygen species (ROS) production. This increased pH, coupled with T-MP-driven lysosomal centripetal migration, promotes the formation of MHC class I-tumor antigen peptide complexes. Concurrently, endocytosis of T-MPs results in the upregulation of CD80 and CD86. T-MP-increased ROS activate lysosomal Ca2+ channel Mcoln2, leading to Ca2+ release. Released Ca2+ activates transcription factor EB (TFEB), a lysosomal master regulator that directly binds to CD80 and CD86 promoters, promoting gene expression. These findings elucidate a pathway through which DCs efficiently present tumor antigen from T-MPs to CD8+ T cells, potentiating T-MPs as a novel tumor cell-free vaccine with clinical applications. Cancer Immunol Res; 6(9); 1057-68. ©2018 AACR.

Exosomes and Immune Response in Cancer: Friends or Foes?

Exosomes are a type of extracellular vesicle whose study has grown exponentially in recent years. This led to the understanding that these structures, far from being inert waste by-products of cellular functioning, are active players in intercellular communication mechanisms, including in the interactions between cancer cells and the immune system. The deep comprehension of the crosstalk between tumors and the immune systems of their hosts has gained more and more importance, as immunotherapeutic techniques have emerged as viable options for several types of cancer. In this review, we present a comprehensive, updated, and elucidative review of the current knowledge on the functions played by the exosomes in this crosstalk. The roles of these vesicles in tumor antigen presentation, immune activation, and immunosuppression are approached as the relevant interactions between exosomes and the complement system. The last section of this review is reserved for the exploration of the results from the first phase I to II clinical trials of exosomes-based cell-free cancer vaccines.