Dendritic Cells In Lymph Nodes Research Articles

Dimethyl-Dioctadecyl-Ammonium Bromide/Poly(lactic acid) Nanoadjuvant Enhances the Immunity and Cross-Protection of an NM2e-Based Universal Influenza Vaccine.

For most frequent respiratory viruses, there is an urgent need for a universal influenza vaccine to provide cross-protection against intra- and heterosubtypes. We previously developed an Escherichia coli fusion protein expressed extracellular domain of matrix 2 (M2e) and nucleoprotein, named NM2e, and then combined it with an aluminum adjuvant, forming a universal vaccine. Although NM2e has demonstrated a protective effect against the influenza virus in mice to some extent, further improvement is still needed for the induction of immune responses ensuring adequate cross-protection against influenza. Herein, we fabricated a cationic solid lipid nanoadjuvant using poly(lactic acid) (PLA) and dimethyl-dioctadecyl-ammonium bromide (DDAB) and loaded NM2e to generate an NM2e@DDAB/PLA nanovaccine (Nv). In vitro experiments suggested that bone marrow-derived dendritic cells incubated with Nv exhibited ∼4-fold higher antigen (Ag) uptake than NM2e at 16 h along with efficient activation by NM2e@DDAB/PLA Nv. In vivo experiments revealed that Ag of the Nv group stayed in lymph nodes (LNs) for more than 14 days after initial immunization and DCs in LNs were evidently activated and matured. Furthermore, the Nv primed T and B cells for robust humoral and cellular immune responses after immunization. It also induced a ratio of IgG2a/IgG1 higher than that of NM2e to a considerable extent. Moreover, NM2e@DDAB/PLA Nv quickly restored body weight and improved survival of homo- and heterosubtype influenza challenged mice, and the cross-protection efficiency was over 90%. Collectively, our study demonstrated that NM2e@DDAB/PLA Nv could offer notable protection against homo- and heterosubtype influenza virus challenges, offering the potential for the development of a universal influenza vaccine.

Abstract 5761: A nanoplatform based on an in situ tumor vaccine and activation of STING and TLR7/8 pathways for enhanced NSCLC immunotherapy

Abstract Background: Immunotherapy has emerged as a promising treatment for tumors following surgical, radiotherapy, and chemotherapy interventions. Therapeutic tumor vaccines are considered highly effective in eliminating tumors and preventing their recurrence and metastasis due to their ability to induce or enhance T cell-mediated immune responses. However, the therapeutic efficacy of these vaccines is impeded by the heterogeneity present both between and within tumors. In contrast, in situ tumor vaccines, prepared from autologous antigens in tumor patients, present another promising strategy for generating comprehensive immune responses. Methods: In this study, we designed a multifunctional nanopolymer, the transformable nanoassembly PEG-Ce6@PAEMA/R848. This assembly includes the photosensitizer polyethylene glycol-chlorin-e6 (PEG-Ce6), the tumor pH-sensitive polymer poly(2-azepane ethyl methacrylate) (PAEMA), and the immune adjuvant Resiquimod (R-848). The objective is to confirm the activation of bone marrow-derived dendritic cells (DCs) at the cellular level. Subsequently, we investigated the maturation of DCs in lymph nodes and tumor sites in vivo. Results: In the particle characterization process, successful synthesis of nanoparticles was achieved, along with the verification of their acid-responsive function and toxic effects. Furthermore, in vitro experiments demonstrated the activation of bone marrow-derived dendritic cells (DCs) (Figure 1).To further investigate the in vivo vaccine effects, C57BL/6 mice were euthanized, and lymph nodes were extracted to examine the accumulation of FITC-PAEMA. It can be observed that, due to the reduction in size of the particles in the tumor acidic environment, the immune adjuvant can easily enter the lymph nodes. Activation of the STING pathway in dendritic cells within the lymph nodes was detected through qPCR. The maturation of dendritic cells (DCs) in the lymph nodes was determined using flow cytometry (Figure 2). Conclusions: In this study, we developed a straightforward yet potent strategy focused on in situ tumor targeting. This approach effectively inhibits tumor growth while inducing immunogenic cell death and eliciting a systemic anti-tumor immune response against cancer cells. Additionally, we intend to validate the therapeutic efficacy of this strategy on metastatic and distal tumors in subsequent investigations. Citation Format: Haiyu Zhou, Hengliang Hou, Bin Xu, Yucheng Huang, Hongrui Qiu. A nanoplatform based on an in situ tumor vaccine and activation of STING and TLR7/8 pathways for enhanced NSCLC immunotherapy [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 5761.

Abstract 6686: The mechanism of gut microbiome-mediated immune activation on the clinical efficacy of PD-1 blocking treatment in solid tumors

Abstract Gut microbiota is associated with antitumor efficacy of immune checkpoint blockade therapies, yet the mechanism is not largely understood. Here, we show that a novel bacterial strain of Ruminococcaceae isolated from the feces of patients who respond to PD-1 (programmed cell death 1) blockade efficiently primes/activates tumor-specific CD8+ T cells through effective stimulation/maturation of CD103+ dendritic cells (DCs) during migration from the gut to the tumor microenvironment (TME). The administration of this bacteria strain with PD-1 blockade significantly inhibited tumor growth, even when adding them to fecal transplantation of non-responder patients in animal models. Mechanistically, the bacterial strain promoted the IRF8-driven differentiation of CD103+ DCs by stimulating multiple Toll-like receptors and the accumulation of these DCs in tumors and tumor-draining lymph nodes. These CD103+ DCs prolonged engagement with cognate antigen-specific CD8+ T cells, which induced the activation of CD8+ T cells specific for a wide variety of tumor antigens and fostered their PD-1 expression through enhanced T-cell activation signals with NFATc1 nuclear translocation, thereby leading to abundant PD-1+CD8+ T cells, a key effector cell population in PD-1 blockade, with a broader T-cell receptor repertoire in the TME. Our findings with novel single bacterium isolated from feces of responder patients demonstrate the mode of action by gut microbiota to augment antitumor immunity. Citation Format: Nina Yi-Tzu Lin, Shota Fukuoka, Daisuke Motooka, Yuko Shigeno, Takuma Irie, Dieter M. Tourlousse, Kazutoshi Murotomi, Yuji Sekiguchi, Hideyuki Tamaki, Mariko Shindo, Takahiro Tsuji, Hiroaki Wake, Koichi Goto, Toshihiko Doi, Kohei Shitara, Keisuke Watanabe, Yuka Maeda, Shota Nakamura, Yoshimi Benno, Hiroyoshi Nishikawa, Shohei Koyama. The mechanism of gut microbiome-mediated immune activation on the clinical efficacy of PD-1 blocking treatment in solid tumors [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 6686.

Uplifting Antitumor Immunotherapy with Lymph-Node-Targeted and Ratio-Controlled Codelivery of Tumor Cell Lysate and Adjuvant.

Cancer vaccines provide a potential strategy to cure patients. Their clinical utilization and efficacy is, however, limited by incomplete coverage of tumor neoantigens and unspecific and restricted activation of dendritic cells (DCs). Tumor cell lysates (TCLs) containing a broad spectrum of neoantigens, while are considered ideal in formulating personalized vaccines, induce generally poor antigen presentation and transient antitumor immune response. Here, intelligent polymersomal nanovaccines (PNVs) that quantitatively coload, efficiently codeliver, and responsively corelease TCL and CpG adjuvant to lymph node (LN) DCs are developed to boost antigen presentation and to induce specific and robust antitumor immunity. PNVs carrying CpG and ovalbumin (OVA) markedly enhance the maturation, antigen presentation, and downstream T cell activation ability of bone-marrow-derived dendritic cells and induce strong systemic immune response after tail base injection. Remarkably, PNVs carrying CpG and TCL cure 85% of B16-F10 melanoma-bearing mice and generate long-lasting anticancer immune memory at a low dose, protecting all cured mice from tumor rechallenge. These LN-directed PNVs being highly versatile and straightforward opens a new door for personalized cancer vaccines.

Yinxieling decoction ameliorates psoriasis by regulating the differentiation and functions of Langerhans cells via the TGF-β1/PU.1/IL-23 signal axis.

Langerhans cells (LCs) play a critical role in skin immune responses and the development of psoriasis. Yinxieling (YXL) is a representativeChinese herbal medicine for the treatment of psoriasis in South China. It was found to improve psoriasis without obvious side effects in the clinic. Here we attempted to clarify whether and how YXL regulates the differentiation and functions of LCs in Imiquimod (IMQ)-induced psoriasis in vivo and induced LCs in vitro. The Psoriasis Area Severity Index (PASI) score was used to evaluate the efficacy of YXL for IMQ-induced psoriasis-like mice. Flow cytometry was utilized to analyze the effects of YXL, to regulate the differentiation, migration, maturation, and antigen presentation of LCs. The results show that YXL significantly alleviated skin inflammation, as reduced in PASI score and classic psoriasis characteristics in pathological sections. Although there was no effect on the proportion of total DCs in the skin-draining lymph nodes, the expression of epidermal LCs and its transcription factor PU.1 were both markedly inhibited. LCs were also prevented from migrating from epidermal to skin-draining lymph nodes and mature. In addition, the number of LCs carrying antigens in the epidermis increased, which suggested that YXL could effectively prevent LCs from presenting antigens. In vitro, YXL had a significant impact on inhibiting the differentiation of LCs. Further data showed that YXL decreased the relative expression of transforming growth factor-β (TGFβ) messenger RNA (mRNA) and interleukin-23 (IL-23) mRNAs. Thus, YXL alleviates psoriasis by regulating differentiation, migration, maturation, and antigen presentation via the TGFβ/PU.1/IL-23 signal axis.

Preparation and characterization of pickering emulsion stabilized by lovastatin nanoparticles for vaccine adjuvants

While research on mevalonate inhibitors as vaccine adjuvants has made great progress to enhance the effectiveness of the vaccine, co delivery of lovastatin and antigens (OVA) remains an enormous challenge. Here, we encapsulated lovastatin into PLGA nanoparticles. PLGA loading lovastatin was further emulsified with squalene to prepare Pickering emulsion. The emulsification conditions of Pickering emulsion were optimized, and the optimal preparation conditions were obtained. After loading lovastatin and OVA, the size and zeta potential of LS-PPAS/OVA was 1043.33 nm and –22.07 mv, the adsorption rate of OVA was 63.34 %. The adsorbing of LS-PLGA nanoparticles on the surface of squalene in Pickering emulsions was demonstrated by Fluorescent confocal microscopy. After immunization, LS-PPAS enhanced the activation of dendritic cells in lymph nodes, further study found LS-PPAS not only elicited elevated levels of OVA-specific IgG and its subtypes, but also promoted the secretion of TNF-α, IFN-γ, and IL-6 in serum as a marker of cellular immunity. Importantly, LS-PPAS showed sufficient security through monitoring levels of biochemical parameters in serum and pathological observation of organ following vaccinations. LS-PPAS may act as a promising vaccine carrier to produce strong humoral and cellular immunity with acceptable safety.

Biologically Self-Assembled Tumor Cell-Derived Cancer Nanovaccines as an All-in-One Platform for Cancer Immunotherapy.

Tumor cell-derived cancer nanovaccines introduce tumor cell-derived components as functional units that endow the nanovaccine systems with some advantages, especially providing all potential tumor antigens. However, cumbersome assembly steps, potential risks of exogenous adjuvants, as well as insufficient lymph node (LN) targeting and dendritic cell (DC) internalization limit the efficacy and clinical translation of existing tumor cell-derived cancer nanovaccines. Herein, we introduced an endoplasmic reticulum (ER) stress inducer α-mangostin (αM) into tumor cells through poly(d, l-lactide-co-glycolide) nanoparticles and harvested biologically self-assembled tumor cell-derived cancer nanovaccines (αM-Exos) based on the biological process of tumor cell exocytosing nanoparticles through tumor-derived exosomes (TEXs). Besides presenting multiple potential antigens, αM-Exos inherited abundant 70 kDa heat shock proteins (Hsp70s) upregulated by ER stress, which can not only act as endogenous adjuvants but also improve LN targeting and DC internalization. Following subcutaneous injection, αM-Exos efficiently migrated to LNs and was expeditiously endocytosed by DCs, delivering tumor antigens and adjuvants to DCs synchronously, which then powerfully triggered antitumor immune responses and established long-term immune memory. Our study exhibited an all-in-one biologically self-assembled tumor cell-derived cancer nanovaccine platform, and the fully featured cancer nanovaccines assembled efficiently through this platform are promising for desirable cancer immunotherapy.

Age-Associated Reduction of Sinus Macrophages in Human Mesenteric Lymph Nodes.

There are numerous macrophages and dendritic cells in lymph nodes (LNs). Recent studies have highlighted that sinus macrophages (SMs) in LNs possess antigen-presenting capabilities and are related to anti-cancer immune responses. In this study, we assessed the distribution of SMs in mesenteric LNs removed during surgery for colorectal cancer. A marked reduction of SMs was noted in elderly patients, particularly those over 80 years old. We observed a disappearance of CD169-positive cells in LNs where SMs were reduced. In silico analysis of publicly available single-cell RNA sequencing data from LNs revealed that CD169-positive macrophages express numerous genes associated with antigen presentation and lymphocyte proliferation, similar to dendritic cells' functions. In conclusion, our study demonstrates that SMs, potentially crucial for immune activation, diminish in the LNs of elderly patients. This reduction of SMs may contribute to the immune dysfunction observed in the elderly.

Biomimetic fusion liposomes boosting antitumor immunity and promote memory T cell differentiation to inhibit postoperative recurrence of breast cancer

For most solid tumors, surgery is still the most effective treatment. However, postoperative recurrence is the main reason for the failure of surgical treatment of malignant tumors. It is urgent to develop new nanomedicine systems to inhibit postoperative recurrence. Here, we designed a tumor cell membrane fusion liposome loaded AIE photosensitizer and Metformin named TMFL to inhibit postoperative recurrence. First, thanks to the homing effect of tumor cell membranes, TMFL can enter tumor tissues through active targeting. Under light irradiation, TMFL can produce singlet oxygen (1O2), which promoted immunogenic cell death (ICD) of tumor cells, thereby inducing dendritic cell (DC) maturation and stimulating T cell immunity. Metformin released by TMFL further promoted T cell differentiation into Central Memory T cell (Tcm) and inhibited tumor recurrence. The results of experiments showed that TMFL plus light treatment increased the content of mature DC in lymph nodes. In addition, TMFL can effectively promote the differentiation of T cells into Tcm, increase the content of T cells in recurrent tumor tissue, and inhibit the tumor recurrence. In view of the current major problems such as postoperative tumor recurrence, our TMFL system has a good clinical application potential.

Antigen-specific T cell activation through targeted delivery of in-situ generated antigen and calcium ionophore to enhance antitumor immunotherapy

Recent advances in adoptive T-cell therapy have delivered impressive therapeutic outcomes by instigating enduring anti-tumor responses. Nonetheless, achieving specific T-cell activation remains a challenge due to several factors. Some cancer cells evade T-cell recognition due to the scarcity of tumor-specific T cells and deficiencies in antigen processing or major histocompatibility complex (MHC) presentation. Notably underestimated is the impact of waning T-cell receptor (TCR) expression and the constrained formation of immune synapses (IS) between dendritic cells (DCs) and T cells, impairing T-cell activation. Addressing these complexities, we introduce a pioneering approach featuring the deployment of a gel implant. This implant establishes an on-site antigen reservoir, efficiently targets DCs in lymph nodes, and facilitates calcium ion (Ca2+) delivery. Engineered with controlled swelling, poroelasticity, and resilience, the gel is suitable for surgical implantation. Its ample encapsulation capacity accommodates both photosensitizers and nanoparticles. Upon in situ photothermal irradiation, the gel generates tumor-specific antigens. Furthermore, cationic albumin nanoparticles (cNPs) co-loaded with monophosphoryl lipid A (MPLA) and ionomycin are released, guiding antigens to tumor-draining lymph nodes for DCs maturation. This meticulous process fosters the formation of IS thereby amplifying antigen-specific T-cell activation.

PD-1 Expression By Dendritic Cells Is a Key Regulator of T-Cell Immunity in Cancer

Programmed cell death 1 (PD-1) is an inhibitory receptor expressed on a variety of immune cells and a therapeutic target of checkpoint immunotherapy for cancer patients. PD-1 engagement by PD-L1 or PD-L2 can inhibit activation and expansion of tumor antigen-specific T cells. PD-1 expression in tumor-associated macrophages (TAM) correlates with impaired phagocytosis and antigen presenting function and enhanced immunosuppression. PD-1 is also expressed in dendritic cells (DC) and has been shown to correlate negatively with the outcome of DC-based cancer vaccines. On DC, PD-1 can interact with PD-L1 in cis when both of these receptors are expressed on the same cell surface. DCs are the major antigen presenting cells for cross-presenting tumor antigens to T cells, and PD-L1 upregulation protects them from killing by cytotoxic T lymphocytes, yet dampens the antitumor responses. Very little is known about the specific role of PD-1 on DCs function. In the present study, we sought to understand the role of PD-1 on DCs in the context of cancer. We generated mice with conditional targeting of the Pdcd1 gene (encoding for PD-1) and crossed them with CD11cCre ( Pdcd1 f/fCD11cCre) or Clec9Cre ( Pdcd1 f/fClec9Cre) resulting in specific deletion of PD-1 in DC cells. We used the MC17 fibrosarcoma syngeneic mouse model to investigate the tentative implications of DC-specific PD-1 ablation on anti-tumor responses. We found larger tumor sizes and weights in tumor-bearing Pdcd1 f/fCD11cCre mice compared to their Pdcd1 wt/wtCD11cCre control counterparts. Pdcd1 f/fCD11cCre tumor-bearing mice had significantly higher fractions of DCs in spleens and tumor-draining lymph nodes (tdLNs) but only minimal differences in their activation state and checkpoint marker expression. Similarly, CD4 + and CD8 + T cells from spleens and tdLNs were comparable in percentages and activation states. However, characterization of the immune cells at the tumor site, indicated that Pdcd1 f/fCD11cCre tumor-bearing mice had a more immunosuppressive tumor microenvironment with increased fractions of CD11b +Ly6C hiLy6G -monocytic myeloid derived suppressor cells (M-MDSCs) compared to control tumor-bearing mice. Moreover, flow cytometric analysis revealed that intratumoral M-MDSC in Pdcd1 f/fCD11cCre mice displayed enhanced expression of PD-L1 and CD38, consistent with a more activated and more immunosuppressive phenotype. Characterization of tumor infiltrating CD4 + and CD8 + T cells also revealed vast differences in composition and activation states. Specifically, Pdcd1 f/fCD11cCre mice had larger populations of intratumoral CD3 + T cells, with a greater CD4/CD8 T cell ratio, and higher percentages of CD4 + T regulatory cells. Conversely, intratumoral CD8 + T cells were reduced, and were characterized by diminished expansion of CD8 + T effector cells, and a less activated phenotype as determined by lower expression of CD25, CD69, and GITR. In syngeneic tumor experiments with B16 melanoma expressing ovalbumin (B16-Ova), Pdcd1 f/fCD11cCre mice and Pdcd1 f/fClec9Cre mice similarly had greater tumor sizes and weights compared to their control counterparts. These results indicate that selective ablation of PD-1 in DCs cells confers a more immunosuppressive tumor microenvironment by promoting T regulatory cell expansion and diminishing CD8 + T effector cell activation compromising anti-tumor responses.

Activation dynamics of antigen presenting cells in vivo against Mycobacterium bovis BCG in different immunized route

BackgroundControl of Tuberculosis (TB) infection is mainly the result of productive teamwork between T-cell populations and antigen presenting cells (APCs). However, APCs activation at the site of initiating cellular immune response during BCG early infection is not completely understood.MethodsIn this study, we injected C57BL/6 mice in intravenous (i.v) or subcutaneous (s.c) route, then splenic or inguinal lymph node (LN) DCs and MΦs were sorted, and mycobacteria uptake, cytokine production, antigen presentation activity, and cell phenotype were investigated and compared, respectively.ResultsAg85A-specific T-cell immune response began at 6 days post BCG infection, when BCG was delivered in s.c route, Th17 immune response could be induced in inguinal LN. BCG could induce high level of activation phenotype in inguinal LN MΦs, while the MHC II presentation of mycobacteria-derived peptides by DCs was more efficient than MΦs.ConclusionsThe results showed that BCG immunized route can decide the main tissue of T-cell immune response. Compared with s.c injected route, APCs undergo more rapid cell activation in spleen post BCG i.v infection.

Escherichia coli adhesion protein FimH exacerbates colitis via CD11b+CD103- dendritic cell activation.

Immune stimulators are used to improve vaccine efficiency; however, they are accompanied by various side effects. In previous studies, we reported that the Escherichia coli adhesion protein, FimH, induces immune activity; however, we did not examine any side effects in colon inflammation. FimH was administered orally or intraperitoneally (i.p.) to mice with dextran sulfate sodium (DSS)-induced colitis, and changes in symptoms were observed. Immune cells infiltrated into the colon after the induction of colon inflammation were analyzed using a flow cytometer. Changes in Th1 and Th17 cells that induce colitis were analyzed. Further, mesenteric lymph node (mLN) dendritic cells (DCs) activated by FimH were identified and isolated to examine their ability to induce T-cell immunity. FimH oral and i.p. administration in C57BL/6 mice did not induce inflammation in the colon; however, DSS-induced colitis was exacerbated by oral and i.p. FimH administration. FimH treatment increased immune cell infiltration in the colon compared to that in DSS colitis. Th1 and Th17 cells, which are directly related to colitis, were increased in the colon by FimH; however, FimH did not directly affect the differentiation of these T cells. FimH upregulated the CD11b+CD103- DC activity in the mLNs, which produced the signature cytokines required for Th1 and Th17. In addition, isolated CD11b+CD103- DCs, after stimulation with FimH, directly induced Th1 and Th17 differentiation in a co-culture of CD4 T cells. This study demonstrated the side effects of FimH and indicated that the use of FimH can aggravate the disease in patients with colitis.

Complete remission of tumors in mice with neoantigen-painted exosomes and anti-PD-1 therapy

Neoantigen-based cancer vaccines are emerging as promising tumor therapies, but enhancement of immunogenicity can further improve therapeutic outcomes. Here, we demonstrate that anchoring different peptide neoantigens on subcutaneously administered serum exosomes promote lymph node homing and dendritic cell uptake, resulting in significantly enhanced antigenicity invitro and invivo. Exosomes anchoring of melanoma peptide neoantigens augmented the magnitude and breadth of Tcell response invitro and invivo, to a greater extent with CD8+ Tcell responses. Simultaneous decoration of different peptide neoantigens on serum exosomes induced potent tumor suppression and neoantigen-specific immune responses in mice with melanoma and colon cancer. Complete tumor eradication and sustainable immunological memory were achieved with neoantigen-painted serum exosome vaccines in combination with programmed cell death protein 1 (PD-1) antibodies in mice with colon cancer. Importantly, human serum exosomes loaded withpeptide neoantigens elicited significant tumor growth retardationand immune responses in human colon cancer 3-dimensional (3D) multicellular spheroids. Our study demonstrates that serum exosomes direct invivo localization, increase dendritic cell uptake, and enhance the immunogenicity of antigenic peptides and thus provides a general delivery tool for peptide antigen-based personalized immunotherapy.

Resveratrol regulates macrophage recruitment and M1 macrophage polarization and prevents corneal allograft rejection in rats.

Resveratrol is an immune modulator that can reduce M1 macrophage polarization in vitro. Reducing macrophage recruitment and M1 polarization can prevent corneal allograft rejection (CGR). In this study, rat corneal allograft rejection models were established to explore the effects of resveratrol on CGR and macrophages and the underlying mechanisms after corneal transplantation. Corneal allograft models were established, and 100 mg/kg resveratrol was injected intraperitoneally. The corneal allografts were assessed clinically using the Holland rejection scoring system, anterior segment photography, and anterior segment optical coherence tomography. Corneal macrophages, pro-inflammatory cytokines, and corneal lymphatic vessels were detected using hematoxylin and eosin staining, immunofluorescence staining, and real-time quantitative polymerase chain reaction (qRT-PCR). Dendritic cells (DCs) in cervical lymph nodes were explored using flow cytometry. RNA sequencing experiments were conducted to identify the mechanisms through which resveratrol affected CGR. The results were verified using Simple Western analysis. Pro-inflammatory cytokines by macrophages in vitro were measured using qRT-PCR and enzyme-linked immunosorbent assays. Resveratrol significantly prolonged the survival of corneal grafts and reduced graft edema and central corneal thickness. Corneal macrophage recruitment and M1 macrophage polarization decreased significantly after corneal transplantation in the resveratrol group. Resveratrol also reduced pro-inflammatory cytokines in corneal grafts and suppressed the early generation of cornea lymphatic vessels and the recruitment of cornea inflammatory cells 14 days after surgery. Resveratrol decreased the proportion of DCs in ipsilateral cervical lymph nodes. The effect of resveratrol on CGR was related to the phosphatidylinositol 3-kinase/protein kinase-B (PI3K/Akt) pathway. Resveratrol reduced the secretion of pro-inflammatory cytokines by M1 macrophages in vitro. Our findings suggest that resveratrol can reduce corneal macrophage recruitment and M1 macrophage polarization after corneal transplantation in rats and prevent CGR. The PI3K/Akt pathway may be an important mechanism that warrants further research.

Small EV-based delivery of CpG ODNs for melanoma postsurgical immunotherapy

Blocking programmed cell death protein 1 (PD-1) is an effective therapeutic strategy for melanoma. However, patients often develop tumor recurrence postoperatively due to the low response rate to the anti-PD-1 antibody (aPD-1). In this study, we developed an in situ sprayable fibrin gel that contains cytosine-guanine oligodeoxynucleotides (CpG ODNs)-modified ovalbumin (OVA) antigen-expressing bone marrow dendritic cell (DC)-derived small extracellular vesicles (DC-sEVs) and aPD-1. CpG ODNs can activate DCs, which have potent immunostimulatory effects, by stimulating both the maturation and activation of tumor-infiltrating dendritic cells (TIDCs) and DCs in tumor-draining lymph nodes (TDLNs). In addition, DC-sEVs can deliver OVA to the same DCs, leading to the specific expression of tumor antigens by antigen-presenting cells (APCs). In brief, the unique synergistic combination of aPD-1 and colocalized delivery of immune adjuvants and tumor antigens enhances antitumor T-cell immunity, not only in the tumor microenvironment (TME) but also in TDLNs. This effectively attenuates local tumor recurrence and metastasis. Our results suggest that dual activation by CpG ODNs prolongs the survival of mice and decreases the recurrence rate in an incomplete tumor resection model, providing a promising approach to prevent B16-F10-OVA melanoma tumor recurrence and metastasis.

Lymph node dendritic cells harbor inducible replication-competent HIV despite years of suppressive ART

Although gut and lymph node (LN) memory CD4 Tcells represent major HIV and simian immunodeficiency virus (SIV) tissue reservoirs, the study of the role of dendritic cells (DCs) in HIV persistence has long been limited to the blood due to difficulties to access lymphoid tissue samples. In this study, we show that LN migratory and resident DC subpopulations harbor distinct phenotypic and transcriptomic profiles. Interestingly, both LN DC subpopulations contain HIV intact provirus and inducible replication-competent HIV despite the expression of the antiviral restriction factor SAMHD1. Notably, LN DC subpopulations isolated from HIV-infected individuals treated for up to 14 years are transcriptionally silent but harbor replication-competent virus that can be induced upon TLR7/8 stimulation. Taken together, these results uncover a potential important contribution of LN DCs to HIV infection in the presence of ART.

Magnetic Delivery of Antigen-Loaded Magnetic Liposomes for Active Lymph Node Targeting and Enhanced Anti-Tumor Immunity.

Therapeutic cancer vaccines offer the greatest advantage of enhancing antigen-specific immunity against tumors, particularly for immunogenic tumors, such as melanoma. However, clinical responses remain unsatisfactory, primarily due to inadequate T cell priming and the development of acquired immune tolerance. A major obstacle lies in the inefficient uptake of antigen by peripheral dendritic cells (DCs) and their migration to lymph nodes for antigen presentation. In this context, the magnetic delivery of antigen-loaded magnetic liposomes (Ag-MLs) to actively target lymph node, is proposed. These magnetic responsive liposomes contain soluble mouse melanoma lysate and iron oxide nanoparticles in the core, along with the immunostimulatory adjuvant CpG-1826 incorporated into the lipid bilayer. When applied through magnetic targeting in the mouse melanoma model, Ag-MLs accumulate significantly in the target lymph nodes. This accumulation results in increased population of active DCs in lymph nodes and cytotoxic T lymphocytes (CTLs) within tumors, correlating with effective tumor growth inhibition. Overall, this study demonstrates the potential of magnetic targeting as an effective strategy for delivering cancer vaccines and activating the immune response, offering a novel platform for cancer immunotherapies.

A Booster for Radiofrequency Ablation: Advanced Adjuvant Therapy via In Situ Nanovaccine Synergized with Anti-programmed Death Ligand 1 Immunotherapy for Systemically Constraining Hepatocellular Carcinoma.

Radiofrequency ablation (RFA) is one of the most common minimally invasive techniques for treating hepatocellular carcinoma (HCC), which could destroy tumors through hyperthermia and generate massive tumor-associated antigens (TAAs). However, residual malignant tissues or small satellite lesions are hard to eliminate, generally resulting in metastases and recurrence. Herein, an advanced in situ nanovaccine formed by layered double hydroxides carrying cGAMP (STING agonist) (LDHs-cGAMP) and adsorbed TAAs was designed to potentiate the RFA-induced antitumor immune response. As-prepared LDHs-cGAMP could effectively enter cancerous or immune cells, inducing a stronger type I interferon (IFN-I) response. After further adsorption of TAAs, nanovaccine generated sustained immune stimulation and efficiently promoted activation of dendritic cells (DCs). Notably, infiltrations of cytotoxic lymphocytes (CTLs) and activated DCs in tumor and lymph nodes were significantly enhanced after nanovaccine treatment, which distinctly inhibited primary, distant, and metastasis of liver cancer. Furthermore, such a nanovaccine strategy greatly changed the tumor immune microenvironment and promoted the response efficiency of anti-programmed death ligand 1 (αPD-L1) immunotherapy, significantly arresting the poorly immunogenic hepa1-6 liver cancer progression. These findings demonstrate the potential of nanovaccine as a booster for RFA in liver cancer therapy and provide a promising in situ cancer vaccination strategy.

A conserved N protein nano-vaccine of COVID-19 exerts potent and cross-reactive humoral and cellular immune responses in mice.

As severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mutates continually, the current vaccines are unable to provide sufficient protection. It is important to develop a broad-spectrum vaccine with conserved antigens to prevent variant infection. Here we fused the SARS-CoV-2 N protein with Helicobacter pylori nonheme ferritin to construct a SARS-CoV-2 N-Ferritin nanoparticle vaccine. Compared with the monomer N protein, the N-Ferritin nanoparticles induced more lymph node dendritic cells in mice to trigger adoptive immunity. Following this, the N-Ferritin elicited more robust and long-lasting antibody responses, which had better cross-reactivity with the SARS-CoV N protein. It is also worth noting that higher levels of N-specific IgG and IgA were distributed in the lungs of N-Ferritin-immunized mice. Furthermore, the N-Ferritin nanoparticles also resulted higher proportion of interferon-γ+ CD8+ T cells, CD8+ Tcm cells, and T cells with cross-reactivity in SARS-CoV-2, SARS-CoV, and Middle East respiratory syndrome-related coronavirus. The conserved N-based nanoparticles could provide a promising vaccine developing strategy against SARS-CoV-2 variants and other coronaviruses.