Efficient Antigen Presentation Research Articles

Construction of lymph nodes-targeting tumor vaccines by using the principle of DNA base complementary pairing to enhance anti-tumor cellular immune response

Tumor vaccines, a crucial immunotherapy, have gained growing interest because of their unique capability to initiate precise anti-tumor immune responses and establish enduring immune memory. Injected tumor vaccines passively diffuse to the adjacent draining lymph nodes, where the residing antigen-presenting cells capture and present tumor antigens to T cells. This process represents the initial phase of the immune response to the tumor vaccines and constitutes a pivotal determinant of their effectiveness. Nevertheless, the granularity paradox, arising from the different requirements between the passive targeting delivery of tumor vaccines to lymph nodes and the uptake by antigen-presenting cells, diminishes the efficacy of lymph node-targeting tumor vaccines. This study addressed this challenge by employing a vaccine formulation with a tunable, controlled particle size. Manganese dioxide (MnO2) nanoparticles were synthesized, loaded with ovalbumin (OVA), and modified with A50 or T20 DNA single strands to obtain MnO2/OVA/A50 and MnO2/OVA/T20, respectively. Administering the vaccines sequentially, upon reaching the lymph nodes, the two vaccines converge and simultaneously aggregate into MnO2/OVA/A50-T20 particles through base pairing. This process enhances both vaccine uptake and antigen delivery. In vitro and in vivo studies demonstrated that, the combined vaccine, comprising MnO2/OVA/A50 and MnO2/OVA/T20, exhibited robust immunization effects and remarkable anti-tumor efficacy in the melanoma animal models. The strategy of controlling tumor vaccine size and consequently improving tumor antigen presentation efficiency and vaccine efficacy via the DNA base-pairing principle, provides novel concepts for the development of efficient tumor vaccines.Graphical

The Mechanism of Action of Cancer Therapeutic Vaccines and Their Application Prospects

The complexity of cancer as a global health problem has also led to the development of various novel therapeutics, including prophylactic vaccines. Scientific breakthroughs and technological developments have changed cancer research; since cancer is a complicated disease with many factors, more and better vaccines are required. The research stresses the worldwide influence of cancer and modern therapeutic approaches, such as vaccination. With advances in molecular and cellular biology, cancer therapeutic vaccination studies have been advanced; the discovery of tumor markers and advances in immunology and cancer therapies have changed. In contrast to chemotherapy and radiation, immunotherapy revolutionized treatment. The cancer therapeutic vaccines elicit antigen-specific T cell responses, helper T cell stimulation, and innate immune cells; the research indicates that these vaccines use various means to arouse the body's defensive mechanism against cancer. Complex tools are explained by figures 1 and 2, which depict CD4+ T cells and innate immunity cells. Vaccines can be peptide/protein-based, whole-cell- or nucleic acid-based by application or clinical trial. Each category is looked at for its significant successes, triumphs, and failures: dendritic cell vaccines, the efficiency of antigen presentation, and clinical trial success. Cancer-therapeutic vaccines and immune checkpoint inhibitors are synergistic. Expanding the range of cancer vaccine antigens depends on finding added tumor-associated antigens and immunological checkpoints. However, there are flaws in cancer therapeutic vaccines, despite progress; tumor heterogeneity, immune evasion, and Safety are among concerns today. Recognizing these problems sets the stage for later chapters of optimization and new approaches.

Abstract 6553: Targeting macrophages and regulatory T cells improves response to chemotherapy in high-grade serous ovarian cancer

Abstract Despite the initial response to chemotherapy, most high-grade serous ovarian cancer (HGSOC) patients will suffer disease relapse within two years of diagnosis with no currently successful immunotherapy options.We performed single-cell RNA sequencing (scRNAseq) on omental metastasis from HGSOC patients. Analysis of 64,097 immune cells showed that neoadjuvant chemotherapy (NACT) induced immunosuppressive mechanisms that counteracted its potentially positive effects. We showed that while NACT enhanced phagocytosis and antigen presentation, this was counterbalanced by upregulation of Stabilin1 (STAB1) in eight out of eleven macrophage subpopulations we identified. The NACT associated increase in macrophage STAB1 expression was validated in a separate cohort of eighty HGSOC patients at the protein level. STAB1 is a macrophage scavenger receptor that transports phagocytosed targets to undergo significant lysosomal degradation reducing the efficiency of antigen presentation. In vitro anti-stabilin1 antibody (anti-stab1 ab) -treated macrophages had significantly reduced antigen degradation and higher CD11C expression than isotype-treated ones. Furthermore, T cells co-cultured with anti-stab1 ab -treated macrophages had increased T cell proliferation and killing.We identified thirteen CD4 subpopulations by scRNAseq, five of which were Tregs. We showed that NACT significantly upregulated and activated Tregs. Tregs displayed a shared developmental trajectory with naïve and effector T cells suggesting that those are induced rather than natural Tregs. This was supported by TCR clonal sharing between Tregs and other effector cells. In vitro T cells treated with FOXP3 anti-sense oligonucleotide (ASO), AZD8701, had an anti-tumor cytokine profile and enhanced tumor cell killing. Analysis of 69,781 scRNAseq cells from control and chemotherapy-treated HGSOC syngeneic mouse model showed similar responses. In two HGSOC syngeneic mouse models (HGS2 and 30200), combinations of chemotherapy with anti-stab1 ab and/or Foxp3-ASO significantly increased median survival of mice with established peritoneal disease compared to chemotherapy alone. Bulk RNAseq of tumors treated with anti-stab1 ab were enriched with CXCL9 positive macrophages, while Foxp3-ASO treatment showed significant increase in T helper cell infiltration and activation. Potentially cured long-term survivors (300 days+) were resistant to tumor rechallenge.In a third HGSOC mouse model (60577), in which tumors relapsed after a good initial response to chemotherapy, combinations of chemotherapy with anti-stab1 ab and/or Foxp3-ASO significantly increased the post relapse survival compared to chemotherapy alone.We believe that modulating Tregs and STAB1 could improve response to chemotherapy and can have translational potential as each AZD8701 and a humanized anti-stab1 ab are in phase I clinical trials. Citation Format: Samar Elorbany, Chiara Berlato, Larissa Carnevalli, Simon Barry, Eleni Maniati, Jun Wang, Ranjit Manchanda, Julia Kzhyshkowska, Frances Balkwill. Targeting macrophages and regulatory T cells improves response to chemotherapy in high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6553.

Abstract 709: Enhancing prostate cancer treatment: Synergistic effects of mechano-thermal focused ultrasound and radiation therapy

Abstract Current treatments for prostate cancer primarily rely on radiation and hormone deprivation therapy, yet they often lack effective immunotherapeutic effects. Furthermore, long-term hormone ablation has side effects, such as, impotency and osteoporosis. Addressing this gap, we introduce an innovative dual-frequency focused ultrasound (FUS) platform for non-ablative focal therapy, which induces protein unfolding, ER stress, and increases heat-shock protein expression along with translocation of endoplasmic reticular chaperone proteins (e.g., calreticulin) on the tumor cell surface, thereby sensitizing them for phagocytosis by dendritic cells for efficient antigen presentation and cross priming. We hypothesized that FUS-mediated acoustic immune priming can be combined with ablative therapies, such as, hormone ablation and/or radiation therapy (RT) for induction of tumor-specific adaptive immune response and better tumor control than monotherapy in murine prostate cancer models. Utilizing murine prostate cancer cell lines, MyC-CaP and RM1, we explored the cellular responses to androgen deprivation, observing distinct sensitivities. Twenty-four hours after FUS treatment tumor cells experienced mechano-thermal stress response with 15-fold increase in Hspa1a expression. Transmission Electron Microscopy studies showed formation of myelin figures, nuclear membrane deformation, and lipid droplet formation. In vivo, the combination of FUS (220w/cm2 intensity for 3 sec at focal point) and RT (8-10 Gy daily x two fractions) markedly delayed tumor growth and achieved complete cure in 14-17% of animals. Through multicolor flow cytometry, we detected significant alterations in the immune microenvironment, including increased CD8+ T cell infiltration and reduced tumor-associated macrophages in the tumor bed. However, we also observed a compensatory rise in pro-tumor immune cells such as PMN-MDSCs and Tregs with significant suppression of eosinophils (p<0.05). Interestingly, there was suppression of splenic PMN-MDSCs, Mo-MDSCs, and tumor draining lymph node macrophages, suggesting systemic immune modulation in peripheral lymphoid organs of FUS+RT-treated tumor-bearing animals. Our findings reveal that the combination therapy of FUS and RT improves tumor control in murine prostate cancer and significantly modulates the systemic and tumor immune microenvironment. This approach offers new avenues for immunotherapy, potentially transforming the treatment landscape for prostate cancer, typically resistant to conventional immunotherapeutic strategies. Citation Format: Soumya Chatterjee, Saurabh Singh, Stephen Barry, Chandan Guha. Enhancing prostate cancer treatment: Synergistic effects of mechano-thermal focused ultrasound and radiation therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 709.

Chikungunya virus infection disrupts MHC-I antigen presentation via nonstructural protein 2.

Infection by chikungunya virus (CHIKV), a mosquito-borne alphavirus, causes severe polyarthralgia and polymyalgia, which can last in some people for months to years. Chronic CHIKV disease signs and symptoms are associated with the persistence of viral nucleic acid and antigen in tissues. Like humans and nonhuman primates, CHIKV infection in mice results in the development of robust adaptive antiviral immune responses. Despite this, joint tissue fibroblasts survive CHIKV infection and can support persistent viral replication, suggesting that they escape immune surveillance. Here, using a recombinant CHIKV strain encoding the fluorescent protein VENUS with an embedded CD8+ T cell epitope, SIINFEKL, we observed a marked loss of both MHC class I (MHC-I) surface expression and antigen presentation by CHIKV-infected joint tissue fibroblasts. Both in vivo and ex vivo infected joint tissue fibroblasts displayed reduced cell surface levels of H2-Kb and H2-Db MHC-I proteins while maintaining similar levels of other cell surface proteins. Mutations within the methyl transferase-like domain of the CHIKV nonstructural protein 2 (nsP2) increased MHC-I cell surface expression and antigen presentation efficiency by CHIKV-infected cells. Moreover, expression of WT nsP2 alone, but not nsP2 with mutations in the methyltransferase-like domain, resulted in decreased MHC-I antigen presentation efficiency. MHC-I surface expression and antigen presentation was rescued by replacing VENUS-SIINFEKL with SIINFEKL tethered to β2-microglobulin in the CHIKV genome, which bypasses the requirement for peptide processing and TAP-mediated peptide transport into the endoplasmic reticulum. Collectively, this work suggests that CHIKV escapes the surveillance of antiviral CD8+ T cells, in part, by nsP2-mediated disruption of MHC-I antigen presentation.

Development of Mannosylated Lipid Nanoparticles for mRNA Cancer Vaccine with High Antigen Presentation Efficiency and Immunomodulatory Capability.

Insufficient accumulation of lipid nanoparticles (LNPs)-based mRNA vaccines in antigen presenting cells remains a key barrier to eliciting potent antitumor immune responses. Herein, we develop dendritic cells (DCs) targeting LNPs by taking advantage of mannose receptor-mediated endocytosis. Efficient delivery of mRNA to DCs is achieved in vitro and in vivo utilizing the sweet LNPs (STLNPs-Man). Intramuscular injection of mRNA vaccine (STLNPs-Man@mRNAOVA ) results in a four-fold higher uptake by DCs in comparison with commercially used LNPs. Benefiting from its DCs targeting ability, STLNPs-Man@mRNAOVA significantly promotes the antitumor performances, showing a comparable therapeutic efficacy by using one-fifth of the injection dosage as the vaccine prepared from normal LNPs, thus remarkably avoiding the side effects brought by conventional mRNA vaccines. More intriguingly, STLNPs-Man@mRNAOVA exhibits the ability to downregulate the expression of cytotoxic T-lymphocyte-associated protein 4 on T cells due to the blockade of CD206/CD45 axis, showing brilliant potentials in promoting antitumor efficacy combined with immune checkpoint blockade therapy.

Development of Mannosylated Lipid Nanoparticles for mRNA Cancer Vaccine with High Antigen Presentation Efficiency and Immunomodulatory Capability

AbstractInsufficient accumulation of lipid nanoparticles (LNPs)‐based mRNA vaccines in antigen presenting cells remains a key barrier to eliciting potent antitumor immune responses. Herein, we develop dendritic cells (DCs) targeting LNPs by taking advantage of mannose receptor‐mediated endocytosis. Efficient delivery of mRNA to DCs is achieved in vitro and in vivo utilizing the sweet LNPs (STLNPs‐Man). Intramuscular injection of mRNA vaccine (STLNPs‐Man@mRNAOVA) results in a four‐fold higher uptake by DCs in comparison with commercially used LNPs. Benefiting from its DCs targeting ability, STLNPs‐Man@mRNAOVA significantly promotes the antitumor performances, showing a comparable therapeutic efficacy by using one‐fifth of the injection dosage as the vaccine prepared from normal LNPs, thus remarkably avoiding the side effects brought by conventional mRNA vaccines. More intriguingly, STLNPs‐Man@mRNAOVA exhibits the ability to downregulate the expression of cytotoxic T‐lymphocyte‐associated protein 4 on T cells due to the blockade of CD206/CD45 axis, showing brilliant potentials in promoting antitumor efficacy combined with immune checkpoint blockade therapy.

Proton-Gradient-Driven Porphyrin-Based Liposome Remote-Loaded with Imiquimod as In Situ Nanoadjuvants for Synergistically Augmented Tumor Photoimmunotherapy.

Cancer immunotherapy is expected to achieve tumor treatment mainly by stimulating the patient's own immune system to kill tumor cells. However, the low immunogenicity of the tumor and the poor efficiency of tumor antigen presentation result in a variety of solid tumors that do not respond to immunotherapy. Herein, we designed a proton-gradient-driven porphyrin-based liposome (PBL) with highly efficient Toll-like receptor 7 (TLR7) agonist (imiquimod, R837) encapsulation (R837@PBL). R837@PBL rapidly released R837 in the acid microenvironment to activate the TLR in the endosome inner membrane to promote bone-marrow-derived dendritic cell maturation and enhance antigen presentation. R837@PBL upon laser irradiation triggered immunogenic cell death of tumor cells and tumor-associated antigen release after subcutaneous injection, activated TLR7, formed in situ tumor nanoadjuvants, and enhanced the antigen presentation efficiency. Photoimmunotherapy promoted the infiltration of cytotoxic T lymphocytes into tumor tissues, inhibited the growth of the treated and abscopal tumors, and exerted highly effective photoimmunotherapeutic effects. Hence, our designed in situ tumor nanoadjuvants are expected to be an effective treatment for treated and abscopal tumors, providing a novel approach for synergistic photoimmunotherapy of tumors.

Antigen-Specific Stimulation of CD8+ T Cells by Murine Bone Marrow-Derived Dendritic Cells After Treatment with Nanoparticles.

The assessment of antigen presentation by dendritic cells and subsequent antigen-dependent activation of T lymphocytes is a critical step underlying the efficacy of nanoparticle-based therapeutic vaccines. Since nanoparticle physicochemical properties determine their interactions with the immune system, the early stages of nanotechnology-based vaccine development commonly involve optimizing the particles' properties to create a formulation with desired stability, antigen release, targeting of desired cell populations, and efficacy. To accelerate this process, in vitro models suitable for the rapid assessment of a novel vaccine candidate's efficacy are highly desirable. One such model is described in this protocol. Herein, nanoparticles are formulated to deliver a model antigen, SIINFEKL (OVA257-264), the immunodominant class I peptide derived from ovalbumin. These nanoparticles are added to the culture of murine bone marrow-derived dendritic cells, which are subsequently co-incubated with CD8+ T cells from OT-I transgenic mice. The efficient antigen presentation by dendritic cells results in the antigen-dependent proliferation of CD8+ T cells, which is detected by flow cytometry.

Mechanism, applications and of mRNA vaccines

In recent years, infectious diseases such as novel coronavirus pneumonia, influenza, and tuberculosis have brought great social and economic burdens to the world. Vaccination is the most effective and economical intervention to control the spread of infectious diseases, save lives and protect people's health. mRNA vaccine is expected to be a new type of infectious disease vaccine. Compared with traditional vaccines, mRNA vaccines have many advantages, such as high efficiency, safety, short production cycle, low cost, etc. However, the stability of mRNA vaccines is poor. However, mRNA vaccines have poor stability and low delivery efficiency, and their clinical applications are greatly restricted. Therefore, current and future research focuses on the design of advanced and tolerable delivery systems to improve the efficiency of antigen expression and presentation, as well as the optimization of mRNA structure to prolong and control the duration of expression, under the premise of ensuring the safety of vaccines. This review summarizes the history, classification, principles and mechanisms of mRNA vaccines, and briefly discusses the current challenges and future directions for developing mRNA vaccines for different diseases.

Safe and efficient oral allergy immunotherapy using one-pot-prepared mannan-coated allergen nanoparticles

Allergen immunotherapy (AIT) is the only curative treatment for allergic diseases. However, AIT has many disadvantages related to efficiency, safety, long-term duration, and patient compliance. Dendritic cells (DCs) have an important role in antigen-specific tolerance induction; thus, DC-targeting strategies to treat allergies such as glutaraldehyde crosslinked antigen to mannoprotein (MAN) have been established. However, glutaraldehyde crosslinking may reduce the antigen presentation efficiency of DCs. To overcome this, we developed a MAN-coated ovalbumin (OVA) nanoparticle (MDO), which uses intermolecular disulfide bond to crosslink OVA and MAN. MDO effectively targeted DCs resulting in tolerogenic DCs, and promoted higher antigen presentation efficiency by DCs compared with OVA or glutaraldehyde crosslinked nanoparticles. In vitro and in vivo experiments showed that DCs exposed to MDO induced Treg cells. Moreover, MDO had low reactivity with anti-OVA antibodies and did not induce anaphylaxis in allergic mice, demonstrating its high safety profile. In a mouse model of allergic asthma, MDO had significant preventative and therapeutic effects when administered orally or subcutaneously. Therefore, MDO represents a promising new approach for the efficient and safe treatment of allergies.

Integration of bioinformatics and machine learning strategies identifies APM-related gene signatures to predict clinical outcomes and therapeutic responses for breast cancer patients

BackgroundTumor antigenicity and efficiency of antigen presentation jointly influence tumor immunogenicity, which largely determines the effectiveness of immune checkpoint blockade (ICB). However, the role of altered antigen processing and presentation machinery (APM) in breast cancer (BRCA) has not been fully elucidated. MethodsA series of bioinformatic analyses and machine learning strategies were performed to construct APM-related gene signatures to guide personalized treatment for BRCA patients. A single-sample gene set enrichment analysis (ssGSEA) algorithm and weighted gene co-expression network analysis (WGCNA) were combined to screen for BRCA-specific APM-related genes. The non-negative matrix factorization (NMF) algorithm was used to divide the cohort into different clusters and the fgsea algorithm was applied to investigate the altered signaling pathways. Random survival forest (RSF) and the least absolute shrinkage and selection operator (Lasso) Cox regression analysis were combined to construct an APM-related risk score (APMrs) signature to predict overall survival. Furthermore, a nomogram and decision tree were generated to improve predictive accuracy and risk stratification for individual patients. Based on Tumor Immune Dysfunction and Exclusion (TIDE) method, random forest (RF) and Lasso logistic regression model were combined to establish an APM-related immunotherapeutic response score (APMis). Finally, immune infiltration, immunomodulators, mutational patterns, and potentially applicable drugs were comprehensively analyzed in different APM-related risk groups. IHC staining was used to assess the expression of APM-related genes in clinical samples. ResultsIn this study, APMrs and APMis showed favorable performances in risk stratification and therapeutic prediction for BRCA patients. APMrs exhibited more powerful prognostic capacity and accurate survival prediction compared to conventional clinicopathological features. APMrs was closely associated with distinct mutational patterns, immune cell infiltration and immunomodulators expression. Furthermore, the two APM-related gene signatures were independently validated in external cohorts with prognosis or immunotherapeutic responses. Potential applicable drugs and targets were mined in the APMrs-high group. APM-related genes were further validated in our in-house samples. ConclusionThe APM-related gene signatures established in our study could improve the personalized assessment of survival risk and guide ICB decision-making for BRCA patients.

Redirecting Antigens by Engineered Photosynthetic Bacteria and Derived Outer Membrane Vesicles for Enhanced Cancer Immunotherapy.

Significant strides have been made in the development of cancer vaccines to combat malignant tumors. However, the natural immunosuppressive environment within tumors, known as the tumor microenvironment (TME), hampers the uptake and presentation of antigens by antigen-presenting cells (APCs) within the tumor itself. This limitation results in inadequate activation of immune responses against cancer. In contrast, immune cells in peritumoral tissue maintain their normal functions. In this context, we present an interesting approach to enhance cancer immunotherapy by utilizing engineered photosynthetic bacteria (PSB) and their outer membrane vesicles (OMVPSB) to capture and transport antigens to the outer regions of the tumor. We modified PSB with maleimide (PSB-MAL), which, when exposed to near-infrared (NIR) laser-mediated photothermal therapy (PTT), induced extensive cancer cell death and the release of tumor antigens. Subsequently, the NIR-phototactic PSB-MAL transported these tumor antigens to the peripheral regions of the tumor under NIR laser exposure. Even more intriguingly, PSB-MAL-derived OMVPSB-MAL effectively captured and delivered antigens to tumor-draining lymph nodes (TDLNs). This facilitated enhanced antigen presentation by mature and fully functional APCs in the TDLNs. This intricate communication network between PSB-MAL, the OMVPSB-MAL, and APCs promoted the efficient presentation of tumor antigens in the tumor periphery and TDLNs. Consequently, there was a notable increase in the infiltration of cytotoxic T lymphocytes (CTLs) into the tumor, triggering potent antitumor immune responses in both melanoma and breast cancer models. This cascade of events resulted in enhanced suppression of tumor metastasis and recurrence, underscoring the robust efficacy of our approach. Our interesting study, harnessing the potential of bacteria and OMVs to redirect tumor antigens for enhanced cancer immunotherapy, provides a promising path toward the development of personalized cancer vaccination strategies.

Dendritic cell hybrid nanovaccine for mild heat inspired cancer immunotherapy

Cancer therapeutic vaccine can induce antigen-specific immune response, which has shown great potential in cancer immunotherapy. As the key factor of vaccine, antigen plays a central role in eliciting antitumor immunity. However, the insufficient antigen delivery and low efficiency of antigen presentation by dendritic cells (DCs) have greatly restricted the therapeutic efficiency of vaccine. Here we developed a kind of DC hybrid zinc phosphate nanoparticles to co-deliver antigenic peptide and photosensitive melanin. Owing to the chelating ability of Zn2+, the nanoparticles can co-encapsulate antigenic peptide and melanin with high efficiency. The nanovaccine showed good physiological stability with the hydration particle size was approximately 30 nm, and zeta potential was around − 10 mV. The nanovaccine showed homologous targeting effect to DCs in vivo and in vitro, efficiently delivering antigen to DCs. Meanwhile, the nanovaccine could effectively reflux to the tumor-draining lymph nodes. When combined with near-infrared irradiation, the nanovaccine induced effective mild heat in vitro and in vivo to promote antigen presentation. After administrating to MC38 tumor-bearing mice, the hybrid nanovaccine effectively promoted the maturation of DCs, the expansion of cytotoxic T lymphocytes and helper T cells, and the secretion of immunostimulatory cytokines, thereby significantly inhibiting tumor growth.Graphical

Carbopol dispersed PAA-modified UIO-66 with high colloidal stability as a combination nano-adjuvant boosts immune response and protection against pseudorabies virus in mice and pigs.

Although inactivated vaccines have higher safety than live-attenuated vaccines in the control of pseudorabies virus (PRV), their protection efficacy is limited due to insufficient immunogenicity when used alone. High-performance adjuvants that can potentiate immune responses are highly desirable to improve the protection efficacy of inactivated vaccines. In this work, we have developed U@PAA-Car, a Carbopol dispersed zirconium-based metal-organic framework UIO-66 modified by polyacrylic acid (PAA), as a promising adjuvant for inactivated PRV vaccines. The U@PAA-Car has good biocompatibility, high colloidal stability, and antigen (vaccine) loading capacity. It significantly potentiates humoral and cellular immune responses over either U@PAA, Carbopol, or commercial adjuvants such as Alum and biphasic 201 by inducing a higher specific antibody titer, IgG2a/IgG1 ratio, cell cytokine secretion, and splenocyte proliferation. A protection rate of over 90% was observed in challenge tests in the model animal mice and the host animal pigs, which is much higher than that observed with commercial adjuvants. The high performance of the U@PAA-Car is attributed to antigen sustainable release at the injection site and highly efficient antigen internalization and presentation. In conclusion, this work not only demonstrates a great potential of the developed U@PAA-Car nano-adjuvant for the inactivated PRV vaccine but also gives a preliminary explanation of its action mechanism. STATEMENT OF SIGNIFICANCE: We have developed a Carbopol dispersed PAA-modified zirconium-based metal-organic framework UIO-66 (U@PAA-Car) as a promising combination nano-adjuvant for the inactivated PRV vaccine. The U@PAA-Car induced higher specific antibody titers and IgG2a/IgG1 ratio, increased cell cytokines secretion, and better splenocyte proliferation than U@PAA, Carbopol, and the commercial adjuvants Alum and biphasic 201, indicating that it induces a significant potentiation of humoral and cellular immune response. In addition, much higher protection rates were achieved with the U@PAA-Car-adjuvanted PRV vaccine in mice and pigs challenge than those observed from the commercial adjuvant groups. This work not only demonstrates the great potential of the U@PAA-Car nano-adjuvant in an inactivated PRV vaccine but also gives a preliminary explanation of its action mechanism.

Orchestrating antigen delivery and presentation efficiency in lymph node by nanoparticle shape for immune response.

Activating humoral and cellular immunity in lymph nodes (LNs) of nanoparticle-based vaccines is critical to controlling tumors. However, how the physical properties of nanovaccine carriers orchestrate antigen capture, lymphatic delivery, antigen presentation and immune response in LNs is largely unclear. Here, we manufactured gold nanoparticles (AuNPs) with the same size but different shapes (cages, rods, and stars), and loaded tumor antigen as nanovaccines to explore their disparate characters on above four areas. Results revealed that star-shaped AuNPs captured and retained more repetitive antigen epitopes. On lymphatic delivery, both rods and star-shaped nanovaccines mainly drain into the LN follicles region while cage-shaped showed stronger paracortex retention. A surprising finding is that the star-shaped nanovaccines elicited potent humoral immunity, which is mediated by CD4+ T helper cell and follicle B cell cooperation significantly preventing tumor growth in the prophylactic study. Interestingly, cage-shaped nanovaccines preferentially presented peptide-MHC I complexes to evoke robust CD8+ T cell immunity and showed the strongest therapeutic efficacy when combined with the PD-1 checkpoint inhibitor in established tumor study. These results highlight the importance of nanoparticle shape on antigen delivery and presentation for immune response in LNs, and our findings support the notion that different design strategies are required for prophylactic and therapeutic vaccines.

Polymeric nanoparticles for DNA vaccine-based cancer immunotherapy: a review.

Cancer is one of the leading causes of death and mortality in the world. There is an essential need to develop new drugs or therapeutic approaches to manage treatment-resistant cancers. Cancer immunotherapy is a type of cancer treatment that uses the power of the body's immune system to prevent, control, and eliminate cancer. One of the materials used as a vaccine in immunotherapy is DNA. The application of polymeric nanoparticles as carriers for DNA vaccines could be an effective therapeutic approach to activate immune responses and increase antigen presentation efficiency. Various materials have been used as polymeric nanoparticles, including: chitosan, poly (lactic-co-glycolic acid), Polyethylenimine, dendrimers, polypeptides, and polyesters. Application of these polymer nanoparticles has several advantages, including increased vaccine delivery, enhanced antigen presentation, adjuvant effects, and more sustainable induction of the immune system. Besides many clinical trials and commercial products that were developed based on polymer nanoparticles, there is still a need for more comprehensive studies to increase the DNA vaccine efficiency in cancer immunotherapy using this type of carrier.

In the absence of DEC-205, Enhanced inflammation in the CNS is Associated with Reduced numbers of IL-10-producing CD4+ T-cells During WNV encephalitis.

Abstract West Nile Virus (WNV), a mosquito-borne single-stranded RNA flavivirus, can cause significant human morbidity and mortality. Previous studies have shown that dendritic cells (DCs) within the central nervous system (CNS) are required to reactivate antiviral effector T-cell responses that restrict WNV replication and limit immunopathology within the CNS. Among these DCs, one subset expressing DEC-205 accumulates within the CNS during WNV encephalitis. DEC-205, an endocytic receptor highly expressed on conventional DCs (cDCs), mediates the efficient processing and presentation of antigens in vivo, leading to either tolerance or immunity depending on DC maturation status, suggesting that DEC-205+ DCs play an immunoregulatory role in the CNS during WNV infection. However, the contributions of CNS-localized DEC-205+ DCs in programming WNV-specific T-cell immunity remains poorly understood. In preliminary experiments, WNV-infected DEC-205 −/−mice exhibited increased susceptibility to WNV infection, more severe clinical signs of disease, and loss of virologic control with early entry into the CNS despite the increased trafficking, activation, and effector response of CD4+ and CD8+ T cells. We found that this uncontrolled inflammatory response was associated with a lack of IL-10-expressing CD4+ T regulatory cell (T reg) expansion that occurs typically during acute WNV infection. Thus, the enhanced inflammatory response in the absence of DEC-205 was coupled with a failure to protect against WNV infection and neuroinvasive disease. Taken together, DEC-205-expressing DCs regulate the degree and balance of the antiviral immune response to WNV infection within the CNS by activating T regs. NIH SC3GM130472

Nanodrug Inducing Autophagy Inhibition and Mitochondria Dysfunction for Potentiating Tumor Photo-Immunotherapy.

Anticancer immunotherapy is hampered by the poor tumor immunogenicity and immunosuppressive tumor microenvironment (TME). Herein, a liposome nanodrug co-encapsulating doxycycline hydrochloride (Doxy) and chlorin e6 (Ce6) to simultaneously induce autophagy inhibition and mitochondria dysfunction for potentiating tumor photo-immunotherapy is developed. Under near infrared laser irradiation, Ce6 generates cytotoxic reactive oxygen species (ROS) and elicits robust photodynamic therapy (PDT)-induced immunogenic cell death (ICD) for immunosuppressive TME remodeling. In addition, Doxy induced mitochondria dysfunction, which increases ROS generation and enhances PDT to exert more potent killing effect and more powerful ICD. Meanwhile, Doxy increases MHC-I expression on tumor cells surface by efficient autophagy inhibition, leading to more efficient antigen presentation and CTLs recognition to increase tumor immunogenicity. The nanodrugs elicit remarkable antitumor therapy by combining Ce6-mediated PDT and Doxy-induced autophagy inhibition and mitochondria dysfunction. The developed nanodrugs represent a highly efficient strategy for improving cancer immunotherapy.

TLR4 agonist activity of Alcaligenes lipid a utilizes MyD88 and TRIF signaling pathways for efficient antigen presentation and T cell differentiation by dendritic cells.

Alcaligenes faecalis was previously identified as an intestinal lymphoid tissue-resident commensal bacteria, and our subsequent studies showed that lipopolysaccharide and its core active element (i.e., lipid A) have a potent adjuvant activity to promote preferentially antigen-specific Th17 response and antibody production. Here, we compared A. faecalis lipid A (ALA) with monophosphoryl lipid A, a licensed lipid A-based adjuvant, to elucidate the immunological mechanism underlying the adjuvant properties of ALA. Compared with monophosphoryl lipid A, ALA induced higher levels of MHC class II molecules and costimulatory CD40, CD80, and CD86 on dendritic cells (DCs), which in turn resulted in strong T cell activation. Moreover, ALA more effectively promoted the production of IL-6 and IL-23 from DCs than did monophosphoryl lipid A, thus leading to preferential induction of Th17 and Th1 cells. As underlying mechanisms, we found that the ALA-TLR4 axis stimulated both MyD88- and TRIF-mediated signaling pathways, whereas monophosphoryl lipid A was biased toward TRIF signaling. These findings revealed the effects of ALA on DCs and T cells and its induction pattern on signaling pathways.