Immune Memory Formation Research Articles

Repeated LPS induces training and tolerance of microglial responses across brain regions

BackgroundNeuroinflammation is involved in the pathogenesis of almost every central nervous system disorder. As the brain’s innate immune cells, microglia fine tune their activity to a dynamic brain environment. Previous studies have shown that repeated bouts of peripheral inflammation can trigger long-term changes in microglial gene expression and function, a form of innate immune memory.Methods and resultsIn this study, we used multiple low-dose lipopolysaccharide (LPS) injections in adult mice to study the acute cytokine, transcriptomic, and microglia morphological changes that contribute to the formation of immune memory in the frontal cortex, hippocampus, and striatum, as well as the long-term effects of these changes on behavior. Training and tolerance of gene expression was shared across regions, and we identified 3 unique clusters of DEGs (2xLPS-sensitive, 4xLPS-sensitive, LPS-decreased) enriched for different biological functions. 2xLPS-sensitive DEG promoters were enriched for binding sites for IRF and NFkB family transcription factors, two key regulators of innate immune memory. We quantified shifts in microglia morphological populations and found that while the proportion of ramified and rod-like microglia mostly remained consistent within brain regions and sexes with LPS treatment, there was a shift from ameboid towards hypertrophic morphological states across immune memory states and a dynamic emergence and resolution of events of microglia aligning end-to-end with repeated LPS.ConclusionsTogether, findings support the dynamic regulation of microglia during the formation of immune memories in the brain and support future work to exploit this model in brain disease contexts.

Early life psychosocial stress increases binge-like ethanol consumption and CSF1R inhibition prevents stress-induced alterations in microglia and brain macrophage population density.

An early life psychosocial stress (PSS) exposure increases ethanol consumptionMicroglial inhibition during PSS trends towards reducing ethanol consumptionBinge ethanol consumption increases microglial count and alters cell proximityEarly life PSS alters microglial responsivity to binge ethanol consumptionMicroglial inhibition may prevent microglial innate immune memory formation.

Nano-Pulse Treatment Overcomes the Immunosuppressive Tumor Microenvironment to Elicit In Situ Vaccination Protection against Breast Cancer.

We previously reported that nano-pulse treatment (NPT), a pulsed power technology, resulted in 4T1-luc mammary tumor elimination and a strong in situ vaccination, thereby completely protecting tumor-free animals against a second live tumor challenge. The mechanism whereby NPT mounts effective antitumor immune responses in the 4T1 breast cancer predominantly immunosuppressive tumor microenvironment (TME) remains unanswered. In this study, orthotopic 4T1 mouse breast tumors were treated with NPT (100 ns, 50 kV/cm, 1000 pulses, 3 Hz). Blood, spleen, draining lymph nodes, and tumors were harvested at 4-h, 8-h, 1-day, 3-day, 7-day, and 3-month post-treatment intervals for the analysis of frequencies, death, and functional markers of various immune cells in addition to the suppressor function of regulatory T cells (Tregs). NPT was verified to elicit strong in situ vaccination (ISV) against breast cancer and promote both acute and long-term T cell memory. NPT abolished immunosuppressive dominance systemically and in the TME by substantially reducing Tregs, myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs). NPT induced apoptosis in Tregs and TAMs. It also functionally diminished the Treg suppression capacity, explained by the downregulation of activation markers, particularly 4-1BB and TGFβ, and a phenotypic shift from predominantly activated (CD44+CD62L-) to naïve (CD44-CD62L+) Tregs. Importantly, NPT selectively induced apoptosis in activated Tregs and spared effector CD4+ and CD8+ T cells. These changes were followed by a concomitant rise in CD8+CD103+ tissue-resident memory T cells and TAM M1 polarization. These findings indicate that NPT effectively switches the TME and secondary lymphatic systems from an immunosuppressive to an immunostimulatory state, allowing cytotoxic T cell function and immune memory formation to eliminate cancer cells and account for the NPT in situ vaccination.

Self-adjuvanting polymeric nanovaccines enhance IFN production and cytotoxic T cell response

Vaccines represent one of the most powerful and cost-effective innovations for controlling a wide range of infectious diseases caused by various viruses and bacteria. Unlike mRNA and DNA-based vaccines, subunit vaccines carry no risk of insertional mutagenesis and can be lyophilized for convenient transportation and long-term storage. However, existing adjuvants are often associated with toxic effect and reactogenicity, necessitating expanding the repertoire of adjuvants with better biocompatibility, for instance, designing self-adjuvating polymeric carriers. We herein report a novel subunit vaccine delivery platform constructed via in situ free radical polymerization of C7A (2-(Hexamethyleneimino) ethyl methacrylate) and acrylamide around the surface of individual protein antigens. Using ovalbumin (OVA) as a model antigen, we observed substantial increases in both diameter (∼70 nm) and surface potential (−1.18 mV) following encapsulation, referred to as n(OVA)C7A. C7A's ultra pH sensitivity with a transition pH around 6.9 allows for rapid protonation in acidic environments. This property facilitates crucial processes such as endosomal escape and major histocompatibility complex (MHC)-I-mediated antigen presentation, culminating in the substantial CD8+ T cell activation. Additionally, compared to OVA nanocapsules without the C7A components and native OVA without modifications, we observed heightened B cell activation within the germinal center, along with remarkable increases in serum antibody and cytokine production. It's important to note that mounting evidence suggests that adjuvant effects, particularly its targeted stimulation of type I interferons (IFNs), can contribute to advantageous adaptive immune responses. Beyond its exceptional potency, the nanovaccine also demonstrated robust formation of immune memory and exhibited a favorable biosafety profile. These findings collectively underscore the promising potential of our nanovaccine in the realm of immunotherapy and vaccine development.

Viral rebound occurrence immediately after drug discontinuation involving neither drug resistance nor latent reservoir

Some viruses exhibit “rebound” when the administration of antiviral drugs is discontinued. Viral rebound caused by resistance mutations or latent reservoirs has been studied mathematically. In this study, we investigated the viral rebound due to other causes. Since immunity is weaker during antiviral treatment than without the treatment, drug discontinuation may lead to an increase in the viral load. We analyzed the dynamics of the number of virus-infected cells, cytotoxic T lymphocytes, and memory cells and identified the conditions under which the viral load increased upon drug discontinuation. If drug is administered for an extended period, a viral rebound occurs when the ratio of viral growth rate in the absence to that in the presence of the antiviral drug exceeds the “rebound threshold.” We analyzed how the rebound threshold depended on the patient's conditions and the type of treatment. Mathematical and numerical analyses revealed that rebound after discontinuation was more likely to occur when the drug effectively reduced viral proliferation, drug discontinuation was delayed, and the processes activating immune responses directly were stronger than those occurring indirectly through immune memory formation. We discussed additional reasons for drugs to cause viral rebound more likely.

The Immune System of the Critically Ill Patient

Critically ill patients often experience a dysregulated immune response, leading to immune dysfunction. Sepsis, trauma, severe infections, and certain medical conditions can trigger a state of systemic inflammation, known as the cytokine storm. This hyperactive immune response can cause collateral damage to healthy tissues and organs, exacerbating the patient's condition. On the other hand, some critically ill patients may suffer from immune paralysis which can increase the risk of nosocomial infections.Fever is an evolutionary adaptation that evolved as an effective defense mechanism to fight invading pathogens. By raising body temperature, fever enhances the immune response, inhibits pathogen growth, promotes recovery, and aids in the formation of immune memory. Understanding the role of fever in the context of immune defense is crucial for optimizing medical interventions and supporting the body's natural ability to combat infections.Future Directions: Advancements in immunology research and technology hold promise for better understanding the immune system's complexities in critically ill patients. Personalized medicine approaches may be developed to tailor therapies to individual patients based on their immune profile, optimizing treatment outcomes. Based on recent studies prognostic parameters such as lymphocyte count, IL-10 concentration and mHLA-DR expression can be used to stratify the immunological response pattern in septic patients.Conclusion: The immune system's response in critically ill patients is a multifaceted process, involving intricate interactions between various immune cells, cytokines, and organs. Striking the delicate balance between immune activation and suppression remains a significant challenge in clinical practice. Continued research and therapeutic innovations are vital to improve patient outcomes and reduce the burden of critical illness on healthcare systems.

Inhalable extracellular vesicle delivery of IL-12 mRNA to treat lung cancer and promote systemic immunity.

Lung carcinoma is one of the most common cancers and has one of the lowest survival rates in the world. Cytokines such as interleukin-12 (IL-12) have demonstrated considerable potential as robust tumour suppressors. However, their applications are limited due to off-target toxicity. Here we report on a strategy involving the inhalation of IL-12 messenger RNA, encapsulated within extracellular vesicles. Inhalation and preferential uptake by cancer cells results in targeted delivery and fewer systemic side effects. The IL-12 messenger RNA generates interferon-γ production in both innate and adaptive immune-cell populations. This activation consequently incites an intense activation state in the tumour microenvironment and augments its immunogenicity. The increased immune response results in the expansion of tumour cytotoxic immune effector cells, the formation of immune memory, improved antigen presentation and tumour-specific T cell priming. The strategy is demonstrated against primary neoplastic lesions and provides profound protection against subsequent tumour rechallenge. This shows the potential for locally delivered cytokine-based immunotherapies to address orthotopic and metastatic lung tumours.

Integration of the immune memory into the pathogen-driven MHC polymorphism hypothesis.

Major histocompatibility complex (MHC) genes (referred to as human leukocyte antigen or HLA in humans) are a key component of vertebrate immune systems, coding for proteins which present antigens to T-cells. These genes are outstanding in their degree of polymorphism, with important consequences for human and animal health. The polymorphism is thought to arise from selection pressures imposed by pathogens on MHC allomorphs, which differ in their antigen-binding capacity. However, the existing theory has not considered MHC selection in relation to the formation of immune memory. In this paper, we argue that this omission limits our understanding of the evolution of MHC polymorphism and its role in disease. We review recent evidence that has emerged from the massive research effort related to the SARS-CoV-2 pandemics, and which provides new evidence for the role of MHC in shaping immune memory. We then discuss why the inclusion of immune memory within the existing theory may have non-trivial consequence for our understanding of the evolution of MHC polymorphism. Finally, we will argue that neglecting immune memory hinders our interpretation of empirical findings, and postulate that future studies focusing on pathogen-driven MHC selection would benefit from stratifying the available data according to the history of infection (and vaccination, if relevant).

Lipid-Polymer Hybrid Nanoparticles with Both PD-L1 Knockdown and Mild Photothermal Effect for Tumor Photothermal Immunotherapy.

In developing countries, the incidence of colorectal cancer (CRC) is on the rise. The combination of programmed cell death ligand-1 (PD-L1) siRNA (siPD-L1) and mild photothermal therapy (PTT) is a promising strategy for CRC treatment. In this study, dopamine-modified polyethylenimine (PEI) was prepared to fabricate an IR780 and siPD-L1 codelivery lipid-polymer hybrid nanoparticle (lip@PSD-siP) for the photothermal immunotherapy of CRC. The modification of dopamine can significantly reduce the cytotoxicity of PEI. lip@PSD-siP can be effectively taken up by CT26 cells and successfully escaped from lysosomes after entering the cells for 4 h. After CT26 cells were transfected with lip@PSD-siP, the PD-L1 positive cell rate decreased by 82.4%, and its PD-L1 knockdown effect was significantly stronger than the positive control Lipo3000-siP. In vivo studies showed that lip@PSD-siP-mediated mild PTT and efficient PD-L1 knockdown exhibited primary and distal tumor inhibition, metastasis delay, and rechallenged tumor inhibition. The treatment with lip@PSD-siP significantly promoted the maturation of dendritic cells in lymph nodes. The amount of T cell infiltration in the tumor tissues increased significantly, and the frequency of CD8+ T cells and CD4+ T cells was significantly higher than that of other groups. The percentage of immunosuppressive regulatory cells (Tregs) in the tumor tissue on the treatment side decreased by 88% compared to the PBS group, and the proportion of CD8+CD69+ T cells in the distal tumor tissue was 2.8 times that of the PBS group. The memory T cells of mice in the long-term antitumor model were analyzed. The results showed that after treatment with lip@PSD-siP, the frequency of effector memory T cells (Tem cells) significantly increased, suggesting the formation of immune memory.

Monitoring Melanoma Responses to STING Agonism and Focused Ultrasound Thermal Ablation Using Microneedles and Ultrasensitive Single Molecule Arrays

AbstractReal‐time monitoring of immune state and response to therapy can provide a means to stratify patients and increase the number of responders who will benefit from approved and emerging immunotherapies. The accessibility of immune cells in the skin provides an opportunity for local immune modulation as well as for noninvasive sampling of disease biomarkers in the skin interstitial fluid (ISF). Here, a monitoring strategy for melanoma immunotherapy is investigated by longitudinal sampling of biomarkers in the skin ISF using Hyaluronic acid (HA)‐based microneedles (MNs). Focused ultrasound ablation and delivery of nanoparticulate stimulator of interferon genes agonist are used as model immunotherapies. It is shown that this combination therapy induces potent inflammatory responses in a melanoma mouse model, promoting tumor elimination and immune memory formation. Indeed, quantifying soluble, protein‐based biomarkers following therapy using conventional immunoassay reveals a pronounced proinflammatory program in the tumor. However, conventional assays fail to detect the low concentration of biomarkers in plasma and in MN‐sampled ISF. It is shown that ultrasensitive single molecule arrays (Simoa) effectively detected proinflammatory biomarkers that are upregulated in response to the therapy in MN‐sampled ISF, in plasma, and in tumors, supporting the feasibility of monitoring melanoma immunotherapy using MNs.

Abstract CT254: Trial in progress: a first-in-human, phase 1, multicenter dose escalation and dose expansion study of WTX-330 in adult patients with advanced or metastatic solid tumors or non-Hodgkin lymphoma

Abstract Background: Interleukin-12 (IL-12) is a potent proinflammatory cytokine with activating effects on both innate and adaptive immune cells. Though recombinant IL-12 (rIL-12) causes tumor regression with antitumor immune memory formation in a range of immunocompetent mouse models, clinical development of rIL-12 was limited by serious toxicities resulting in several patient deaths. WTX-330 is an engineered cytokine prodrug composed of a wild-type IL-12 heterodimer fused via proprietary cleavable linkers to an inactivation domain and to a half-life extension domain. In the circulation and in normal tissues, WTX-330 is designed to remain inactive and not bind to high-affinity IL-12 receptors. In contrast, proteolytic activation of WTX-330 in the tumor microenvironment is expected to liberate the IL-12 cytokine to stimulate antitumor immunity. Preclinical data show that WTX-330 is activated by a range of dissociated human tumors in vitro but not by normal human cells or by patient serum. Moreover, a WTX-330 murine surrogate molecule has potent antitumor activity as a monotherapy in multiple syngeneic mouse models, including in those resistant to anti-PD-1 therapy. In the MC38 model, the WTX-330 surrogate has a large therapeutic window of 49-fold compared to 5-fold for recombinant chimeric IL-12. Methods: This first-in-human, open-label phase 1 trial is investigating the safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity, and antitumor activity of WTX-330 administered as a monotherapy to patients with advanced or metastatic solid tumors or non-Hodgkin lymphoma (NCT05678998). All patients must have ≥ 1 measurable lesion per RECIST 1.1 and be refractory to all standard of care therapies for their indication. Dose escalation utilizes a Bayesian logistic regression model with overdose control with WTX-330 administered intravenously every two weeks in 28-day cycles. Dose expansion is anticipated to include two arms (A, B) of 20 patients each. Patients eligible for Arm A will have tumor types for which immune checkpoint inhibitors (ICIs) are indicated but demonstrate either primary or secondary resistance to this therapy. Primary resistance is defined as disease progression or SD < 6 months as the best response after at least 6 weeks of exposure to PD-(L)1 inhibitors. Secondary resistance is defined as disease progression ≥ 6 months after initiation of PD-(L)1 inhibitors in patients who received clinical benefit (i.e., CR, PR, or SD > 6 months). Patients eligible for Arm B will have any solid tumor for which ICI therapy is not indicated, or non-Hodgkin lymphoma. Pre- and on-treatment tumor biopsies, archival tumor tissue, and blood samples will be assayed for a range of exploratory biomarkers. As of January 12, 2023, the trial is opening sites and recruiting patients. Citation Format: Ildefonso Ismael Rodriguez-Rivera, Justin C. Moser, Mateusz Opyrchal, Aparna R. Parikh, Saero Park, Marissa Bruno, Paul Windt, Kulandayan K. Subramanian, Sameer S. Chopra, Randi Isaacs. Trial in progress: a first-in-human, phase 1, multicenter dose escalation and dose expansion study of WTX-330 in adult patients with advanced or metastatic solid tumors or non-Hodgkin lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT254.

Abstract 4142: CD4 T cell-driven response to immunotherapy against mouse melanoma tumors

Abstract Using an in situ vaccine (ISV) regimen that includes a combination therapy of radiation (given at D0) with hu14.18-IL2 immunocytokine [anti-GD2 linked to IL2, (Anyxis Immuno-Oncology GmbH (Austria)); given at D5-D9], we can cure mice of large B78 melanoma tumors (B78s). GD2 is expressed on many solid tumors, including most melanomas, and is not often expressed on immune cells. Mice cured with ISV of B78 tumors demonstrate long-term immune memory, with mice rejecting tumor rechallenge >180 days post initial cure of tumor. Traditionally, immune effector memory is thought to be mediated via CD8 T cells, which require antigen presentation via MHC Class I (MHCI). However, B78s express little to no MHCI, but do express MHCII when stimulated with IFNγ. Expressed on 50-70% of melanomas in humans, the role of MHCII on response is unclear. We explored implications of MHCII and MHCI expression on response (initial response to ISV and memory response). Mice bearing B78s depleted of NK cells or CD8 T cells during ISV respond to therapy, but mice depleted of CD4 T cells fail to respond to ISV. Likewise, B78-cured mice depleted of NK and CD8 T cells during rechallenge are able to reject the B78 tumor rechallenge, whereas those depleted of CD4 T cells failed to reject their B78 rechallenge. Together these data suggest that CD4 T cells are required for the initial antitumor response to ISV as well as for immune memory formation and function. Tumors and tumor draining lymph nodes were harvested during ISV treatment in B78-bearing mice at D8 and assessed by scRNAseq, flow cytometry, IncuCyte and ImageStream (live-cell imaging assays), and IsoPlexis (cytokine profile). Though not required for initial or memory response, both CD8 and NK cells are activated and exhibit cytotoxic phenotypes in the tumor microenvironment (TME). Furthermore, a population of cells co-expressing both GD2 and CD45 was observed in the TME following ISV that was not observed in untreated mice. These GD2+/CD45+ cells were predominantly CD4+ T cells incorporate patchy GD2 expression on their surface via trogocytosis. We hypothesize that the interaction between MHCII on tumor cells and CD4 T cell receptors mediates the trogocytosis, activating CD4 T cells to function as helper T cells, initiating a cascade of antitumor immunity, as well as causing direct CD4 T cell-mediated cytotoxicity. MHCII is expressed on some melanoma tumors, and its expression has been correlated with a positive response to immunotherapies. MHCII expression on tumors can directly engage CD4 cytotoxic T cells, suggesting an important role in the response to immunotherapy for CD4 T cells in melanoma tumors that express MHCII. Understanding the cellular and molecular mechanisms involved in the ISV-induced immune recognition and destruction of B78 may guide future improvements of this clinically-relevant immunotherapy regimen. Citation Format: Amy K. Erbe, Arika S. Feils, Alina Hampton, Dan Spiegelman, Noah Tsarovsky, Anna Hoefges, Peter M. Carlson, Alex Pieper, Callie Haertle, Mackenzie Heck, Sabrina VandenHeuvel, Lizzie Frankel, Lauren Zebertavage, Alexa Heaton, Zachary S. Morris, Ravi Patel, Alexander Rakhmilevich, Paul M. Sondel. CD4 T cell-driven response to immunotherapy against mouse melanoma tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4142.

Microglial immune regulation by epigenetic reprogramming through histone H3K27 acetylation in neuroinflammation.

Epigenetic reprogramming is the ability of innate immune cells to form memories of environmental stimuli (priming), allowing for heightened responses to secondary stressors. Herein, we explored microglial epigenetic marks using the known inflammagen LPS as a memory priming trigger and Parkinsonian-linked environmental neurotoxic stressor manganese (Mn) as the secondary environmental trigger. To mimic physiological responses, the memory priming trigger LPS treatment was removed by triple-washing to allow the cells' acute inflammatory response to reset back before applying the secondary insult. Our results show that after the secondary Mn insult, levels of key proinflammatory markers, including nitrite release, iNOS mRNA and protein expression, Il-6, Il-α and cytokines were exaggerated in LPS-primed microglia. Our paradigm implies primed microglia retain immune memory that can be reprogrammed to augment inflammatory response by secondary environmental stress. To ascertain the molecular underpinning of this neuroimmune memory, we further hypothesize that epigenetic reprogramming contributes to the retention of a heightened immune response. Interestingly, Mn-exposed, LPS-primed microglia showed enhanced deposition of H3K27ac and H3K4me3 along with H3K4me1. We further confirmed the results using a PD mouse model (MitoPark) and postmortem human PD brains, thereby adding clinical relevance to our findings. Co-treatment with the p300/H3K27ac inhibitor GNE-049 reduced p300 expression and H3K27ac deposition, decreased iNOS, and increased ARG1 and IRF4 levels. Lastly, since mitochondrial stress is a driver of environmentally linked Parkinson's disease (PD) progression, we examined the effects of GNE-049 on primary trigger-induced mitochondrial stress. GNE-049 reduced mitochondrial superoxide, mitochondrial circularity and stress, and mitochondrial membrane depolarization, suggesting beneficial consequences of GNE-049 on mitochondrial function. Collectively, our findings demonstrate that proinflammatory primary triggers can shape microglial memory via the epigenetic mark H3K27ac and that inhibiting H3K27ac deposition can prevent primary trigger immune memory formation and attenuate subsequent secondary inflammatory responses.

The adaptive immune system in early life: The shift makes it count.

Respiratory infectious diseases encountered early in life may result in life-threatening disease in neonates, which is primarily explained by the relatively naive neonatal immune system. Whereas vaccines are not readily available for all infectious diseases, vaccinations have greatly reduced childhood mortality. However, repeated vaccinations are required to reach protective immunity in infants and not all vaccinations are effective at young age. Moreover, protective adaptive immunity elicited by vaccination wanes more rapidly at young age compared to adulthood. The infant adaptive immune system has previously been considered immature but this paradigm has changed during the past years. Recent evidence shows that the early life adaptive immune system is equipped with a strong innate-like effector function to eliminate acute pathogenic threats. These strong innate-like effector capacities are in turn kept in check by a tolerogenic counterpart of the adaptive system that may have evolved to maintain balance and to reduce collateral damage. In this review, we provide insight into these aspects of the early life's adaptive immune system by addressing recent literature. Moreover, we speculate that this shift from innate-like and tolerogenic adaptive immune features towards formation of immune memory may underlie different efficacy of infant vaccination in these different phases of immune development. Therefore, presence of innate-like and tolerogenic features of the adaptive immune system may be used as a biomarker to improve vaccination strategies against respiratory and other infections in early life.

Macrophages in gouty inflammation

Gout disorder is likely to be the most common cause of inflammatory arthritis. Hyperuricemia leads to formation of poorly soluble crystalline urate salts in tissues and joints, thus being etiological factor of the gout. The review summarizes modern views on the mechanisms of autoinflammation in gout disorder and it provides an outlook for the new treatment approaches. Inflammation in gout is related to phagocytosis of the urate crystals and the macrophagic NLRP3 inflammosome activation. This process consists of preliminary stage and proinflammatory cytokine generation phases. During the preliminary phase, soluble and crystalline urate salts initiate mRNA transcription for IL-1 and other proinflammatory cytokines precursors in macrophages, synthesis of NLRP3 inflammosome components, and formation of immune memory. Enhanced transcription of IL-1 and other cytokine precursors is implemented via PRAS49-AKT-mTOR signaling, IL- 1ra anti-inflammantory factor and TLR-MyD88-IRAK-NF-B pathway; the enhanced synthesis of NLRP3 inflammasome components provided via the TLR-NF-B pathway. The immune memory develops due to the epigenetic modifications, associated with (de-) acetylation and (de-) methylation of histones and DNA. During the next phase, the effect of soluble and crystalline urate salts upon macrophages promotes NLRP3 inflammosome activation, due to the following events: 1. К+, Cl- and Са2+ ionic currents shift; 2. lysosomic and mitochondrial damage, leading to the cathepsin B release and enhancement of reactive oxygen production, respectively; 3. NLRP3 relocation between the endoplasmic reticulum, Golgi complex and cytosol; 4. alteration of the NLRP3 structure due to auxiliary proteins attachment, phosphorylation, ubiquitination and acetylation. The NLRP3 inflammosome activity results into increased caspase 1 production which, in turn, produces IL-1 and pyroptotic pores proteins. The pyroptotic pores allow IL-1 passage, which further amplifies inflammation. During the pyroptosis, soluble and crystalline urate salts release from the cells, further increasing inflammation and tissue damage. Understanding the mechanisms of gout-associated inflammation helps us to formulate promising approaches to development of novel treatments. Macrophages are the key cells to crystal-induced inflammation development. Thus, new biothechnologies based on macrophage engineering may appear to be prospective in gout treatment. In this review, we have analyzed the prospects of M3 phenotype macrophages (AB-M3) usage in therapy, unlike M1 and M2 phenotypes, is able to produce anti-inflammatory cytokines in response to the inflammatory factors and, therefore, to inhibit crystal-induced inflammation. Meanwhile, unlike the anti-IL-1 medications, e.g., canakinumab, targeting a single end product of the gout inflammation (IL-1), AB-M3 macrophages inhibit not only IL-1 production, but also a group of other inflammatory cytokines.

Recent Advances in Engineering Nanomedicines for Second Near-Infrared Photothermal-Combinational Immunotherapy.

Immunotherapy has emerged as one of the major strategies for cancer treatment. Unlike conventional therapeutic methods, immunotherapy can treat both primary and distant metastatic tumors through triggering systematic antitumor immune responses and can even prevent tumor recurrence after causing the formation of immune memory. However, immunotherapy still has the issues of low patient response rates and severe immune-related adverse events in clinical practices. In this regard, the combination of nanomedicine-mediated therapy with immunotherapy can modulate a tumor immunosuppressive microenvironment and thus amplify antitumor immunity. In particular, second near-infrared (NIR-II) photothermal therapy (PTT), which utilizes light conversions to generate heat for killing cancer cells, has shown unique advantages in combining with immunotherapy. In this review, the recent progress of engineering nanomedicines for NIR-II PTT combinational immunotherapy is summarized. The role of nanomedicine-mediated NIR-II PTT in inducing immunogenic cell death and reprogramming the tumor immunosuppressive microenvironment for facilitating immunotherapy are highlighted. The development of NIR-II-absorbing organic and inorganic nonmetal and inorganic metal nanomedicines for the NIR-II PTT combinational immunotherapy of cancer is also introduced in detail. Lastly, the current challenges and future perspectives of these nanomedicines for combinational immunotherapy are proposed.

A HER2 target antibody drug conjugate combined with anti-PD-(L)1 treatment eliminates hHER2+ tumors in hPD-1 transgenic mouse model and contributes immune memory formation.

Disitamab vedotin (RC48) is an HER2-directed antibody-drug conjugate, emerging as an effective strategy for cancer therapy, which not only enhances antitumor immunity in previous animal models but also improves clinical outcomes for patients such as with gastric cancer, urothelium carcinoma, and HER2 low-expressing breast cancer. Here, we explore the combination therapeutic efficacy of this novel HER2-targeting ADC with immune checkpoint inhibitors in a human HER2-expressing syngeneic breast cancer model. The human HER2+ cancer cell line is constructed by stable transfection and individual clones were isolated by single-cell sorting. Flow cytometry was performed to determine its binding activity. Cytotoxic effect was determined using an MTT assay with the supplement of RC48. Human PD-1 transgenic mice were used to analyze the in vivo antitumor effects of the ADC and its combination therapy with PD-1/PD-L1 antibody. The combination of RC48 and PD-1/PD-L1 immune checkpoint inhibition significantly enhanced tumor suppression and antitumor immunity. Tumor rejection in the synergistic groups was accompanied by massive T cell infiltration and immune marker activation. Furthermore, the combination therapy promoted immunological memory formation in the tumor eradication animals, protecting them from tumor rechallenge. A novel HER2-targeting ADC combined with immune checkpoint inhibitors can achieve remarkable effects in mice and elicit long-lasting immune protection in a hHER2+ murine breast cancer model. This study provides insights into the efficacy of RC48 therapeutic activity and a rationale for potential therapeutic combination strategies with immunotherapy.

Local delivery of mRNA-encoded cytokines promotes antitumor immunity and tumor eradication across multiple preclinical tumor models.

Local immunotherapy ideally stimulates immune responses against tumors while avoiding toxicities associated with systemic administration. Current strategies for tumor-targeted, gene-based delivery, however, are limited by adverse effects such as off-targeting or antivector immunity. We investigated the intratumoral administration of saline-formulated messenger (m)RNA encoding four cytokines that were identified as mediators of tumor regression across different tumor models: interleukin-12 (IL-12) single chain, interferon-α (IFN-α), granulocyte-macrophage colony-stimulating factor, and IL-15 sushi. Effective antitumor activity of these cytokines relied on multiple immune cell populations and was accompanied by intratumoral IFN-γ induction, systemic antigen-specific T cell expansion, increased granzyme B+ T cell infiltration, and formation of immune memory. Antitumor activity extended beyond the treated lesions and inhibited growth of distant tumors and disseminated tumors. Combining the mRNAs with immunomodulatory antibodies enhanced antitumor responses in both injected and uninjected tumors, thus improving survival and tumor regression. Consequently, clinical testing of this cytokine-encoding mRNA mixture is now underway.

Brakes off cyclin drives memory

Cancer Cyclin-dependent kinases 4 and 6 (CDK4/6) are enzymes that stimulate cell proliferation. CDK4/6 inhibitor (CDK4/6i) drugs block the signals that instruct tumor cells to divide and have been approved to treat a subset of breast cancers. Heckler et al. and Lelliott et al. found that CDK4/6i can also promote the formation of immune memory to help fight tumors. Short-term treatment of cancer cells with CDK4/6i pushed activated CD8+ T lymphocytes along a memory cell trajectory, which promoted long-term tumor immunity in mice. These findings may guide the design of human clinical trials using CDK4/6i as a cancer pretreatment to kick-start the immune response before the addition of immunotherapeutic agents. Cancer Discov. 10.1158/2159-8290.CD-20-1540, 10.1158/2159-8290.CD-20-1554 (2021).

The Natural History of T Cell Metabolism

The cells of the immune system, particularly the T lymphocytes, have two main features that distinguish them from the cells of other tissues. They proliferate after activation and have the ability to move in tissues and organs. These characteristics compel them to develop metabolic plasticity in order to fulfil their immune function. This review focuses on the different known mechanisms that allow T cells to adapt their metabolism to the real-life circumstances they operate in, whether it is to exit quiescence, to differentiate into effector cells, or to participate in immune memory formation. Some of the metabolic adaptations to environmental variations that T cells are likely to undergo in their immune monitoring function are also discussed.