Long-term Immunological Memory Research Articles

Mesenchymal stromal cells dampen trained immunity in house dust mite-primed macrophages expressing human macrophage migration inhibitory factor polymorphism

BackgroundTrained immunity results in long-term immunological memory, provoking a faster and greater immune response when innate immune cells encounter a secondary, often heterologous, stimulus. We have previously shown that house dust mite (HDM)-induced innate training is amplified in mice expressing the human macrophage migration inhibitory factor (MIF) CATT7 functional polymorphism. AimThis study investigated the ability of mesenchymal stromal cells (MSCs) to modulate MIF-driven trained immunity both in vitro and in vivo. MethodsCompared with wild-type mice, in vivo HDM-primed bone marrow-derived macrophages (BMDMs) from CATT7 mice expressed significantly higher levels of M1-associated genes following lipopolysaccharide stimulation ex vivo. Co-cultures of CATT7 BMDMs with MSCs suppressed this HDM-primed effect, with tumor necrosis factor alpha (TNF-α) being significantly decreased in a cyclooxygenase 2 (COX-2)-dependent manner. Interestingly, interleukin 6 (IL-6) was suppressed by MSCs independently of COX-2. In an in vitro training assay, MSCs significantly abrogated the enhanced production of pro-inflammatory cytokines by HDM-trained CATT7 BMDMs when co-cultured at the time of HDM stimulus on day 0, displaying their therapeutic efficacy in modulating an overzealous human MIF-dependent immune response. Utilizing an in vivo model of HDM-induced trained immunity, MSCs administered systemically on day 10 and day 11 suppressed this trained phenomenon by significantly reducing TNF-α and reducing IL-6 and C-C motif chemokine ligand 17 (CCL17) production. ConclusionsThis novel study elucidates how MSCs can attenuate an MIF-driven, HDM-trained response in CATT7 mice in a model of allergic airway inflammation.

Near-infrared photoimmunotherapy targeting PD-L1: Improved efficacy by preconditioning the tumor microenvironment.

Near-infrared photoimmunotherapy (NIR-PIT) is a new type of cancer therapy that employs antibody-IRDye700DX conjugates (AbPCs) and near-infrared (NIR) light at a wavelength of 689 nm, the excitation wavelength of IR700. Administered intravenously, injected AbPCs bind specifically to cells expressing the target antigen, whereupon NIR light exposure causes rapid, selective killing. This process induces an anticancer T cell response, leading to sustained anticancer host immune response. Programmed cell death ligand-1 (PD-L1) is a major inhibitory immune checkpoint molecule expressed in various cancers. In this study, we first assessed the efficacy of PD-L1-targeted NIR-PIT (αPD-L1-PIT) in immune-competent tumor mouse models. αPD-L1-PIT showed a significant therapeutic effect on the tumor models with high PD-L1 expression. Furthermore, αPD-L1-PIT induced an abscopal effect on distant tumors and long-term immunological memory. In contrast, αPD-L1-PIT was not as effective for tumor models with low PD-L1 expression. To improve the efficacy of PD-L1-targeted NIR-PIT, PEGylated interferon-gamma (IFNγ) was administered with αPD-L1-PIT. The combination therapy improved the treatment efficacy by increasing PD-L1 expression leading to more efficient cell killing by αPD-L1-PIT. Furthermore, the PEGylated IFNγ led to a CD8+ T cell-dominant tumor microenvironment (TME) with an enhanced anticancer T cell response after αPD-L1-PIT. As a result, even so-called cold tumors exhibited complete responses after αPD-L1-PIT. Thus, combination therapy of PEGylated IFNγ and PD-L1-targeted NIR-PIT has the potential to be an important future strategy for cancer immunotherapy.

Abstract LB118: HM16390, a novel long-acting IL-2 analog with fine-tuned binding affinities to IL-2 receptor subunits for favorable safety profile, exhibits potent tumor killing effect in the various tumor syngeneic models

Abstract Although recombinant human IL-2 (rhIL-2, aldesleukin) produced approximately a 15% objective response rate in patients with renal cell carcinoma (RCC) and metastatic melanoma, its IL-2Rα (CD25)-biased binding and short half-life (t1/2 in human: 13-85 min) require a high dose and frequent dosing interval, leading to systemic toxicity such as vascular leak syndrome (VLS) and cytokine release syndrome (CRS). To overcome this limitation, various research groups are developing engineered IL-2 muteins with abolished CD25 binding affinity. While such IL-2 muteins may reduce CD25-mediated toxicity, there is a risk of a lopsided immune response. Furthermore, concomitantly reduced affinity to IL-2Rβ (CD122) may cause insufficient anti-tumor activity. We are developing HM16390, a long-acting IL-2 analog with a significantly increased binding affinity to CD122 for potent tumor killing effect. Simultaneously, optimal binding property to CD25 was introduced for a suppression of uncontrolled systemic immune response via peripheral Treg expansion. From these novel sequence modifications, HM16390 exhibited approximately 14-fold potent activity in human NK and CD8+ T cells compared to rhIL-2 and comparable activity with rhIL-2 in human Tregs (EC50 of STAT5 phosphorylation) without undesired release of cytokines associated with CRS. In B16F10 mouse model, HM16390 has a longer-lasting PK property (t1/2: 14.2~26.0 hr) after single subcutaneous (SC) administration. CD8+ T cells were significantly increased in peripheral blood along with a transient increase of peripheral Tregs, suggesting that HM16390 not only has a significant effect on expansion of CD8+ T cells but can simultaneously modulate exaggerated peripheral immune response. It is also noteworthy that, unlike in the peripheral, Tregs were drastically reduced in the tumor immune microenvironment, and CD8+ T cells were significantly increased. Next, in orthotopic model of mouse RCC (RENCA-luc cell implantation), across treatment groups, 40%(n=4/10) to 80%(n=8/10) of animals achieved complete tumor regression in dose-dependent manner after once weekly SC injection of HM16390 for 4 weeks. Furthermore, tumor nodules were not observed in lung and kidney after intravenous (IV) rechallenge of RENCA cells in the mice cured by HM16390 for at least 4 months after drug discontinuation. This indicates a long-term immunological memory response of generated memory cells by treatment of HM16390. In conclusion, HM16390 demonstrates potent and durable anti-tumor activity in various murine tumor models via its enhanced CD122 binding affinity, and incorporated optimal CD25 binding affinity may alleviate systemic toxicity by immunomodulatory role of peripheral Tregs. Citation Format: Sol-Bi Shin, Jinyoung Kim, Jaehyuk Choi, Seongju Jeong, Yunjae Kim, Jooyun Byun, Sungmin Bae, Daejin Kim, In Young Choi. HM16390, a novel long-acting IL-2 analog with fine-tuned binding affinities to IL-2 receptor subunits for favorable safety profile, exhibits potent tumor killing effect in the various tumor syngeneic models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB118.

Abstract 5303: A novel TIGIT and 4-1BB bispecific antibody, ABL112, exhibits potent in vitro and in vivo antitumor activity through dual immune modulation

Abstract T cell immunoreceptor with Ig and ITIM domains (TIGIT) is an immune checkpoint molecule responsible for delivering inhibitory signals that suppress immune activation. Due to its inhibitory role in the immune response, TIGIT has emerged as a potential therapeutic target for various malignancies, with several clinical trials exploring the use of anti-TIGIT blocking antibodies with anti-PD-(L)1 therapies. Recent reports have indicated elevated expression of 4-1BB within intra-tumoral Tregs. Therefore, we hypothesized that a dual targeting approach involving both TIGIT and 4-1BB could effectively enhance intra-tumoral immunity. ABL112, a First-in-Class bispecific antibody targeting TIGIT and 4-1BB, demonstrated the induction of T cell activation by blocking the TIGIT signaling and TIGIT dependent 4-1BB clustering. By having intact Fc, ABL112 bound to FcγRI and its crosslinking with 4-1BB also induced 4-1BB activation. ABL112 selectively depleted Treg cells but not other T cells in vitro, potentially through antibody-dependent cell-mediated cytotoxicity. ABL112 demonstrated superior efficacy in tumor regression compared to anti-TIGIT monoclonal antibody across various mouse tumor models. Additionally, combining ABL112 with pembrolizumab significantly inhibited tumor growth better than combining anti-TIGIT monoclonal antibody with pembrolizumab. According to immune cell depletion assay, ABL112-mediated tumor suppressive activity was predominantly driven by CD8+ T cells, with a partial tumor reduction by CD4+ T cell or NK cell depletion. Mice with complete remission (CR) were further protected from the tumor re-challenge after 3 months of cessation of ABL112 treatment, and the proportion of tumor-specific memory T cells in the blood increased, suggesting long-term immunological memory has been established. In conclusion, ABL112 exhibited potent in vitro and in vivo anti-tumor activity through multiple mode of action including TIGIT inhibition and 4-1BB activation. These results strongly suggest that ABL112 is an innovative and promising therapeutic option with the combination of anti-PD-(L)1 therapies for cancer patients. Citation Format: Wonjun Son, Yangsoon Lee, Yelim Park, Jonghwa Won. A novel TIGIT and 4-1BB bispecific antibody, ABL112, exhibits potent in vitro and in vivo antitumor activity through dual immune modulation [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 5303.

Measles-specific antibodies loss after a single dose of MMR vaccine in children with oligo-articular JIA on methotrexate treatment: a single-center case-controlled study.

Novel treatments have revolutionized the care and outcome of patients with juvenile idiopathic arthritis (JIA). Patients with rheumatic diseases are susceptible to infections, including vaccine preventable ones, due to waning immunity, failing immune system and immunosuppressive treatment received. However, data regarding long-term immunological memory and response to specific vaccines are limited. Assessment of the impact of methotrexate (MTX) treatment on measles-specific-IgG titers, in children with oligo-JIA previously vaccinated with Measles Mumps Rubella (MMR) vaccine (1 dose); by evaluating the persistence of antibodies produced after measles vaccination while on immunomodulating treatment at 0, 12 and 24months. Single-center controlled study including 54 oligo-JIA patients and 26 healthy controls. Seroprotection rates and measles-specific-IgG titers were measured by ELISA and were expressed as GMCs (Geometric Mean Concentrations).The two groups had similar demographic characteristics, vaccination history and immunization status. Seroprotection rates were adequate for both groups. Nonetheless, measles GMCs were significantly lower in the oligo-JIA compared to the control group at one (p = 0.039) and two years' follow-up (p = 0.021). Children with oligo-JIA on MTX treatment appeared to have lower measles-specific-IgG titers. Further studies are required to assess the long-term immunity conveyed by immunizations given at an early stage in children with rheumatic diseases on synthetic Disease Modifying Antirheumatic Drugs (sDMARDs) and to assess the need for booster doses to subjects at risk.

A Programmable Peptidic Hydrogel Adjuvant for Personalized Immunotherapy in Resected Stage Tumors.

Adjuvant treatment after surgical resection usually plays an important role in delaying disease recurrence. Immunotherapy displays encouraging results in increasing patients' chances of staying cancer-free after surgery, as reported by recent clinical trials. However, the clinical outcomes of current immunotherapy need to be improved due to the limited responses, patient heterogeneity, nontargeted distribution, and immune-related adverse effects. This work describes a programmable hydrogel adjuvant for personalized immunotherapy after surgical resection. By filling the hydrogel in the cavity, this system aims to address the limited secretion of granzyme B (GrB) during immunotherapy and improve the low immunotherapy responses typically observed, while minimizing immune-related side effects. The TLR7/8 agonist imidazoquinoline (IMDQ) is linked to the self-assembling peptide backbone through a GrB-responsive linkage. Its release could enhance the activation and function of immune cells, which will lead to increased secretion of GrB and enhance the effectiveness of immunotherapy together. The hydrogel adjuvant recruits immune cells, initiates dendritic cell maturation, and induces M1 polarized macrophages to reverse the immunosuppressive tumor microenvironment in situ. In multiple murine tumor models, the hydrogel adjuvant suppresses tumor growth, increases animal survival and long-term immunological memory, and protects mice against tumor rechallenge, leading to effective prophylactic and therapeutic responses. This work provides a potential chemical strategy to overcome the limitations associated with immunotherapy.

Tumor Microenvironment-Activatable Nanosystem Capable of Overcoming Multiple Therapeutic Obstacles for Augmenting Immuno/Metal-Ion Therapy.

Abnormal tumor microenvironment (TME) imposes barriers to nanomedicine penetration into tumors and evolves tumor-supportive nature to provide tumor cell protection, seriously weakening the action of antitumor nanomedicines and posing significant challenges to their development. Here, we engineer a TME-activatable size-switchable core-satellite nanosystem (Mn-TI-Ag@HA) capable of increasing the effective dose of therapeutic agents in deep-seated tumors while reversing tumor-supportive microenvironment for augmenting immuno/metal-ion therapy. When activated by TME, the nanosystem disintegrates, allowing ultrasmall-sized Ag nanoparticles to become unbound and penetrate deep into solid tumors. Simultaneously, the nanosystem produces O2 and releases TGF-β inhibitors in situ to drive macrophage M2-to-M1 polarization, increasing intratumoral H2O2 concentration, and ultimately augmenting metal-ion therapy by accelerating hypertoxic Ag+ production. The nanosystem can overcome multiple obstacles that aid in tumor resistance to nanomedicine, demonstrating effective tumor penetration, TME regulation, and tumor inhibition effects. It can provoke long-term immunological memory effects against tumor rechallenge when combined with immune checkpoint inhibitor anti-PD-1. This work provides a paradigm for designing efficient antitumor nanomedicines.

The Modification of H3K4me3 Enhanced the Expression of CgTLR3 in Hemocytes to Increase CgIL17-1 Production in the Immune Priming of Crassostrea gigas.

Increasing evidence confirms that histone modification plays a critical role in preserving long-term immunological memory. Immune priming is a novel form of immunological memory recently verified in invertebrates. Toll-like receptor (TLR) signaling and cytokines have been reported to be involved in the immune priming of the Pacific oyster Crassostrea gigas. In the present study, the expression of Toll-like receptor 3 (CgTLR3), myeloid differentiation factor 88-2 (CgMyd88-2) and interleukin 17-1 (CgIL17-1) was found to be elevated in the hemocytes of C. gigas at 6 h after the secondary stimulation with Vibrio splendidus, which was significantly higher than that at 6 h after the primary stimulation (p < 0.05). A significant increase in histone H3 lysine 4 trimethylation (H3K4me3) enrichment was detected in the promoter region of the CgTLR3 gene at 7 d after the primary stimulation with inactivated V. splendidus (p < 0.05). After the treatment with a histone methyltransferase inhibitor (5'-methylthioadenosine, MTA), the level of H3K4me3 at the promoter of the CgTLR3 gene decreased significantly at 7 d after the primary stimulation with inactivated V. splendidus (p < 0.05), and the expression of CgTLR3, CgMyD88-2 and CgIL17-1 was significantly repressed at 6 h after the secondary stimulation with V. splendidus (p < 0.05). Conversely, the treatment with monomethyl fumarate (MEF, an inhibitor of histone demethylases) resulted in a significant increase in H3K4me3 enrichment levels at the CgTLR3 promoter at 7 d after the primary stimulation (p < 0.05), and the expression of CgTLR3, CgMyD88-2 and CgIL17-1 was observed to increase significantly at 6 h after the secondary stimulation (p < 0.05). These results suggested that H3K4me3 regulated MyD88-dependent TLR signaling in the hemocytes of C. gigas, which defined the role of histone modifications in invertebrate immune priming.

Palmitic acid-capped MIL-101-Al as a nano-adjuvant to amplify immune responses against Pseudomonas aeruginosa.

As a highly contagious opportunistic pathogen, Pseudomonas aeruginosa (P. aeruginosa) is one of the main causes of healthcare-associated infections. The drug-resistant nature of P. aeruginosa can render antibiotic treatments ineffective, leading to a high morbidity and mortality. Higher specificity and reduced toxicity are features of immunotherapy, which can generate robust immune responses and preserve long-term immunological memory to completely eradicate infections. In this study, we developed a type of P. aeruginosa vaccine based on a metal-organic framework. Specifically, MIL-101-Al nanoparticles were synthesized to encapsulate antigens derived from the bacterial lysate (BL) of PAO1, a drug-resistant P. aeruginosa, and the adjuvant unmethylated cytosine-phosphate-guanine oligonucleotide (CpG), which were then modified with palmitic acid (PAA) to obtain MIL-BC@PAA. The stability and biocompatibility were significantly increased by capping with PAA. Moreover, MIL-BC@PAA showed significantly enhanced uptake by antigen presenting cells (APCs), and promoted their maturation. Importantly, immunity studies revealed the greatly elicited antigen-specific humoral and cellular responses, and a protection rate of about 70% was observed in P. aeruginosa-challenged mice. Overall, these results demonstrate the promising potential of MIL-BC@PAA as an ideal nanovaccine for P. aeruginosa vaccination.

PERSPECTIVE FOR APPLYING ANTITUMOR VACCINES

One of the promising areas in immunotherapy are tumour-specific vaccines based on immunocompromised cells. DC-based personalized neoantigenic cellular vaccines have promising antitumor effects in clinical practice. Dendritic cell-based vaccines have a number of advantages, one example being the ability to engage both innate and adaptive immunity, as well as to develop long-term immunological memory against tumor recurrence. DCs are the most professional and consistent antigens and are more effective in activating resting T cells. The review provides the most up-to-date information on cancer vaccines, as well as an analysis of the types of cancer vaccines from domestic and foreign sources. The conclusion of this brief review is the wide variety of types of tumor-specific vaccines and their rapid improvement.

Bimetallic nanoparticles as cascade sensitizing amplifiers for low-dose and robust cancer radio-immunotherapy

Radiotherapy (RT) is one of the most feasible and routinely used therapeutic modalities for treating malignant tumors. In particular, immune responses triggered by RT, known as radio-immunotherapy, can partially inhibit the growth of distantly spreading tumors and recurrent tumors. However, the safety and efficacy of radio-immunotherapy is impeded by the radio-resistance and poor immunogenicity of tumor. Herein, we report oxaliplatin (IV)-iron bimetallic nanoparticles (OXA/Fe NPs) as cascade sensitizing amplifiers for low-dose and robust radio-immunotherapy. The OXA/Fe NPs exhibit tumor-specific accumulation and activation of OXA (II) and Fe2+ in response to the reductive and acidic microenvironment within tumor cells. The cascade reactions of the released metallic drugs can sensitize RT by inducing DNA damage, increasing ROS and O2 levels, and amplifying the immunogenic cell death (ICD) effect after RT to facilitate potent immune activation. As a result, OXA/Fe NPs-based low-dose RT triggered a robust immune response and inhibited the distant and metastatic tumors effectively by a strong abscopal effect. Moreover, a long-term immunological memory effect to protect mice from tumor rechallenging is observed. Overall, the bimetallic NPs-based cascade sensitizing amplifier system offers an efficient radio-immunotherapy regimen that addresses the key challenges.

Antitumor Effect by Either FLASH or Conventional Dose Rate Irradiation Involves Equivalent Immune Responses

Purpose: The capability of ultra-high dose rate FLASH radiotherapy (FLASH) to generate the FLASH effect has opened the possibility to enhance the therapeutic index of radiotherapy. The contribution of the immune response has frequently been hypothesized to account for a certain fraction of the anti-tumor efficacy and tumor kill of FLASH but has yet to be rigorously evaluated. Methods: To investigate the immune response as a potentially important mechanism of the anti-tumor effect of FLASH, various murine tumor models were grafted either subcutaneously or orthotopically into immunocompetent mice, or in moderately and severely immunocompromised mice. Mice were locally irradiated with single dose (20 Gy) or hypo-fractionated regimens (3 × 8 Gy; 2 × 6 Gy), using FLASH (≥ 2000 Gy/s) and Conventional dose rates (0.1 Gy/s, CONV), with/without anti-CTLA-4. Tumor growth was monitored over time, and immune profiling performed. Results: 20 Gy FLASH and CONV were isoeffective in delaying tumor growth in immunocompetent and moderately immunodeficient hosts, and increased tumor doubling time to >14 days vs. >7 days in control animals. Similar observations were obtained with hypo-fractionated scheme, regardless the microenvironment (subcutaneous flank vs. ortho lungs). Interestingly, in profoundly immunocompromised mice, 20 Gy FLASH retained anti-tumor activity and significantly increased tumor doubling time to >14 days vs. >8 days in control animals, suggesting a possible anti-tumor mechanism independent of the immune response. Analysis of the tumor microenvironment showed similar immune profiles after both irradiation modalities with significant decrease of lymphoid cells by ∼40 % and a corresponding increase of myeloid cells. In addition, FLASH and CONV did not increase TGF-β1 levels in tumors as compared to unirradiated control animals. Furthermore, when a complete and long-lasting anti-tumor response was obtained (> 140 days), both modalities of irradiation were able to generate a long-term immunological memory response. Conclusions: The present results clearly document that the tumor responses across multiple immunocompetent and immunodeficient mouse models are largely dose rate independent, and simultaneously contradict a major role of the immune response in the anti-tumor efficacy of FLASH. Therefore, our study indicates that FLASH is as potent as CONV in modulating anti-tumor immune response and can be used as an immunomodulatory agent.

Dendritic Cells Pulsed with Tumor Lysates Induced by Tetracyanotetra(aryl)porphyrazines-Based Photodynamic Therapy Effectively Trigger Anti-Tumor Immunity in an Orthotopic Mouse Glioma Model.

Research in the past decade on immunogenic cell death (ICD) has shown that the immunogenicity of dying tumor cells is crucial for effective anticancer therapy. ICD induction leads to the emission of specific damage-associated molecular patterns (DAMPs), which act as danger signals and as adjuvants to activate specific anti-tumor immune responses, leading to the elimination of tumor cells and the formation of long-term immunological memory. ICD can be triggered by many anticancer treatment modalities, including photodynamic therapy (PDT). However, due to the variety of photosensitizers used and the lack of a universally adopted PDT protocol, there is a need to develop novel PDT with a proven ICD capability. In the present study, we characterized the abilities of two photoactive dyes to induce ICD in experimental glioma in vitro and in vivo. One dye was from the tetracyanotetra(aryl)porphyrazine group with 9-phenanthrenyl (pz I), and the other was from the 4-(4-fluorobenzyoxy)phenyl (pz III) group in the aryl frame of the macrocycle. We showed that after the photosensitizers penetrated into murine glioma GL261 cells, they localized predominantly in the Golgi apparatus and partially in the endoplasmic reticulum, providing efficient phototoxic activity against glioma GL261 cells upon light irradiation at a dose of 20 J/cm2 (λex 630 nm; 20 mW/cm2). We demonstrated that pz I-PDT and pz III-PDT can act as efficient ICD inducers when applied to glioma GL261 cells, facilitating the release of two crucial DAMPs (ATP and HMGB1). Moreover, glioma GL261 cells stimulated with pz I-PDT or pz III-PDT provided strong protection against tumor growth in a prophylactic subcutaneous glioma vaccination model. Finally, we showed that dendritic cell (DC) vaccines pulsed with the lysates of glioma GL261 cells pre-treated with pz-I-PDT or pz-III-PDT could act as effective inducers of adaptive anti-tumor immunity in an intracranial orthotopic glioma mouse model.

Autophagy-amplifying nanoparticles evoke immunogenic cell death combined with anti-PD-1/PD-L1 for residual tumors immunotherapy after RFA

Incomplete radiofrequency ablation (IRFA) triggers mild protective autophagy in residual tumor cells and results in an immunosuppressive microenvironment. This accelerates the recurrence of residual tumors and causes resistance to anti-PD-1/PDL1 therapy, which bringing a great clinical challenge in residual tumors immunotherapy. Mild autophagy activation can promote cancer cell survival while further amplification of autophagy contributes to immunogenic cell death (ICD). To this regard, we constructed active targeting zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) loaded with STF62247 or both STF62247 and BMS202, namely STF62247@ZIF-8/PEG-FA (SZP) or STF62247-BMS202@ZIF-8/PEG-FA (SBZP) NPs. We found that SZP NPs inhibited proliferation and stimulated apoptosis of residual tumor cells exposed to sublethal heat stress in an autophagy-dependent manner. Further results discovered that SZP NPs could amplify autophagy in residual tumor cells and evoke their ICD, which dramatically boosted the maturation of dendritic cells (DCs). Through vaccination experiments, we found for the first time that vaccination with heat + SZP treatment could efficiently suppress the growth of new tumors and establish long-term immunological memory. Furthermore, SBZP NPs could remarkably promote the ICD of residual tumor cells, obviously activate the anti-tumor immune microenvironment, and significantly inhibit the growth of residual tumors. Thus, amplified autophagy coupled with anti-PD-1/PDL1 therapy is potentially a novel strategy for treating residual tumors after IRFA.Graphical

Spleen-targeted neoantigen DNA vaccine forpersonalized immunotherapy of hepatocellularcarcinoma.

Neoantigens are emerging as attractive targets to develop personalized cancer vaccines, but their immunization efficacy is severely hampered by their restricted accessibility to lymphoid tissues where immune responses are initiated. Leveraging the capability of red blood cells (RBCs) to capture and present pathogens in peripheral blood to the antigen-presenting cells (APCs) in spleen, we developed a RBC-driven spleen targeting strategy to deliver DNA vaccine encoding hepatocellular carcinoma (HCC) neoantigen. The DNA vaccine-encapsulating polymeric nanoparticles that were intentionally hitchhiked on the preisolated RBCs could preferentially accumulate in the spleen to promote the neoantigen expression by APCs, resulting in the burst of neoantigen-specific T-cell immunity to prevent tumorigenesis in a personalized manner, and slow down tumor growth in the established aggressively growing HCC. Remarkably, when combined with anti-PD-1, the vaccine achieved complete tumor regression and generated a robust systemic immune response with long-term tumor-specific immunological memory, which thoroughly prevented tumor recurrence and spontaneous lung metastasis. This study offers a prospective strategy to develop personalized neoantigen vaccines for augmenting cancer immunotherapy efficiency in immune "cold" HCC.

Breadth and Durability of SARS-CoV-2-Specific T Cell Responses following Long-Term Recovery from COVID-19.

T cell immunity is crucial for long-term immunological memory, but the profile of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific memory T cells in individuals who recovered from COVID-19 (COVID-19-convalescent individuals) is not sufficiently assessed. In this study, the breadth and magnitude of SARS-CoV-2-specific T cell responses were determined in COVID-19-convalescent individuals in Japan. Memory T cells against SARS-CoV-2 were detected in all convalescent individuals, and those with more severe disease exhibited a broader T cell response relative to cases with mild symptoms. Comprehensive screening of T cell responses at the peptide level was conducted for spike (S) and nucleocapsid (N) proteins, and regions frequently targeted by T cells were identified. Multiple regions in S and N proteins were targeted by memory T cells, with median numbers of target regions of 13 and 4, respectively. A maximum of 47 regions were recognized by memory T cells for an individual. These data indicate that SARS-CoV-2-convalescent individuals maintain a substantial breadth of memory T cells for at least several months following infection. Broader SARS-CoV-2-specific CD4+ T cell responses, relative to CD8+ T cell responses, were observed for the S but not the N protein, suggesting that antigen presentation is different between viral proteins. The binding affinity of predicted CD8+ T cell epitopes to HLA class I molecules in these regions was preserved for the Delta variant and at 94 to 96% for SARS-CoV-2 Omicron subvariants, suggesting that the amino acid changes in these variants do not have a major impact on antigen presentation to SARS-CoV-2-specific CD8+ T cells. IMPORTANCE RNA viruses, including SARS-CoV-2, evade host immune responses through mutations. As broader T cell responses against multiple viral proteins could minimize the impact of each single amino acid mutation, the breadth of memory T cells would be one essential parameter for effective protection. In this study, breadth of memory T cells to S and N proteins was assessed in COVID-19-convalescent individuals. While broad T cell responses were induced against both proteins, the ratio of N to S proteins for breadth of T cell responses was significantly higher in milder cases. The breadth of CD4+ and CD8+ T cell responses was also significantly different between S and N proteins, suggesting different contributions of N and S protein-specific T cells for COVID-19 control. Most CD8+ T cell epitopes in the immunodominant regions maintained their HLA binding to SARS-CoV-2 Omicron subvariants. Our study provides insights into understanding the protective efficacy of SARS-CoV-2-specific memory T cells against reinfection.

Cancer Immunotherapy Based on Cell Membrane-Coated Nanocomposites Augmenting cGAS/STING Activation by Efferocytosis Blockade.

Innate immunity triggered by the cGAS/STING pathway has the potential to improve cancer immunotherapy. Previously, the authors reported that double-stranded DNA (dsDNA) released by dying tumor cells can trigger the cGAS/STING pathway. However, owing to efferocytosis, dying tumor cells are engulfed and cleared before the damaged dsDNA is released; hence, immunologic tolerance and immune escape occur. Herein, a cancer-cell-membrane biomimetic nanocomposites that exhibit tumor-immunotherapeutic effects are synthesized by augmenting the cGAS/STING pathway and suppressing efferocytosis. Once internalized by cancer cells, a combined chemo/chemodynamic therapy would be triggered, which damages their nuclear and mitochondrial DNA. Furthermore, the releasing Annexin A5 protein could inhibit efferocytosis effect and promote immunostimulatory secondary necrosis by preventing phosphatidylserine exposure, resulting in the burst release of dsDNA. These dsDNA fragments, as molecular patterns to immunogenic damage, escape from the cancer cells, activate the cGAS/STING pathway, enhance cross-presentation inside dendritic cells, and promote M1-polarization of tumor-associated macrophages. In vivo experiments suggest that the proposed nanocomposite could recruit cytotoxic T-cells and facilitate long-term immunological memory. Moreover, when combined with immune-checkpoint blockades, it could augment the immune response. Therefore, this novel biomimetic nanocomposite is a promising strategy for generating adaptive antitumor immune responses.

Effect of mevalonate, zoledronate and BCG on monocyte/macrophage phenotype

Cells of innate immunity, mainly monocytes/macrophages, form a long-term nonspecific immunological memory during the initial encounter with the pathogen, the so-called trained immunity. Mevalonate pathway metabolites play an important role in the formation of trained immunity. The aim of this investigation was to study the effect of modulators of mevalonate pathway, mevalonate and zoledronate, on the formation of trained immunity in human and animal monocytes/ macrophages.Material and methods. Human monocyte-like cell lines THP-1 and U-937, peritoneal macrophages of BALB/c mice were used. Trained immunity was induced in vitro by incubation of THP-1 and U-937 monocyte-like cell lines for 24 and 72 hours with inactivated Mycobacteria of BCG vaccine strain, and in vivo by intraperitoneal administration of BCG to BALB/c mice with isolation of peritoneal macrophages on day 7 after infection (lag phase). Cell hyperreactivity was assessed by response to a second stimulus with bacterial lipopolysaccharide (LPS) and mevalonate, zoledranate in the presence or absence of LPS. Lactate, cytokine (IL-1β, TNF-α, IL-10), nitric oxide and glucose level was measured in conditioned media from cells.Results and discussion. The study showed that monocyte-like cell lines THP-1 and U-937 responded differently by cytokine production, lactate, and glucose consumption to BCG stimulus in the presence or absence of lag phase. Mevalonate and zoledronate alone or in combination with LPS also stimulated cytokine production in different ways. The presence of lag phase for human monocyte-like cells is essential for the level of cytokine production and glucose consumption. Peritoneal macrophages have been shown to enhance pro-inflammatory cytokine production in response to LPS, mevalonate, and zoledronate.Conclusions. Mevalonate and zoledronate induce trained immunity in monocytes/macrophages.

Sono-Driven STING Activation using Semiconducting Polymeric Nanoagonists for Precision Sono-Immunotherapy of Head and Neck Squamous Cell Carcinoma.

Immunotherapy has offered new opportunities to treat head and neck squamous cell carcinoma (HNSCC); however, its clinical applications are hindered by modest therapeutic outcomes and the "always-on" pharmacological activity of immunomodulatory agents. Strategies for precise spatiotemporal activation of antitumor immunity can tackle these issues but remain challenging. Herein, a semiconducting polymeric nanoagonist (SPNM) with in situ sono-activatable immunotherapeutic effects for precision sono-immunotherapy of HNSCC is reported. SPNM is self-assembled from a sonodynamic semiconducting polymer core conjugated with a stimulator of interferon genes (STING) agonist (MSA-2) via a singlet oxygen cleavable linker. Under sono-irradiation, SPNM produces singlet oxygen not only to eradicate tumor cells to trigger immunogenic cell death but also to unleash caged STING agonists via the cleavage of diphenoxyethene bonds for in situ activation of the STING pathway in the tumor region. Such sono-driven STING activation mediated by SPNM promotes effector T cell infiltration and potentiates systemic antitumor immunity, eventually leading to tumor growth inhibition and long-term immunological memory. This study thus presents a promising strategy for the precise spatiotemporal activation of cancer immunotherapy.

Integration of Protein Nanocage with CpG Motifs: A Virus-Mimicked Core-Shell Nanostructure to Ignite Antitumor Immunity.

The tumor microenvironment typically possesses immunosuppressive properties that hinder the effectiveness of antitumor immune responses, even in the context of immunotherapies. However, it is observed that pathogenic microorganisms can trigger strong immune responses during infection, offering a potential means to counteract the immunosuppressive environment of tumors. In this study, a protein nanocage called CpG@HBc nanocages (NCs) is developed, which mimics the structure of the hepatitis B virus and combines with an immunostimulatory component known as cytosine phosphoguanosine oligonucleotide (CpG). By delivering these immunostimulatory agents, CpG@HBc NCs are able to effectively reverse the suppressive tumor microenvironment, resulting in the inhibition of poorly immunogenic tumors in mice. Through high-dimensional mass cytometry (CyTOF) analysis, remarkable alterations in immune responses is observed induced by CpG@HBc. Treatment with immunogenic CpG@HBc NCs, along with co-injection of an OX40 agonist, sensitized colorectal cancer tumors to T cell immune responses, resulting in significant impairment of tumor growth and robust immune activation. Furthermore, CpG@HBc NCs induced long-term antitumor immunological memory, protecting tumor-cured mice from tumor rechallenge. Overall, these findings highlight the potential of a virus-inspired protein nanocage to mimic anti-viral immunity and offer a unique therapeutic approach for cancer immunotherapy.