Immune Stimulation Research Articles

Perioperative hypothermia and stress jeopardize anti-metastatic immunity and TLR-9 immune activation: potential mediating mechanisms (experimental studies).

The perioperative period often involves stress responses and surgery-induced hypothermia, which were suggested to hinder anti-metastatic immunity and promote cancer metastasis. During this critical period, immunotherapies are rarely used, given contraindications to surgery. However, recent pre-clinical studies support the feasibility of perioperative TLR-9 activation, using CpG-C. Herein, we employed hypothermic- and normothermic-stress paradigms to assess their impact on perioperative CpG-C immune-stimulation and resistance to experimental hepatic metastasis of CT26 colorectal cancer in BALB/C mice. Perioperative hypothermic wet-cage stress markedly abrogated CpG-C-induced increase in plasma IL-12 levels, a persistent deleterious effect across different CpG-C doses and administration routes. These effects were not attenuated by blocking glucocorticoids, adrenergic, or opioid signaling, nor by adrenalectomy, suggesting direct immunosuppressive impact of hypothermia on immunocytes. Indeed, normothermic wet-cage stress, which induced similar corticosterone response, caused significantly less deleterious effects on IL-12 levels, hepatic NK cell maturation and cytotoxicity, and CT26 metastasis. Additionally, in vitro exposure of PBMCs to 33°C markedly decreased CpG-C-induced IL-12 production. Last, two normothermic stress paradigms, tilt&light and restraint, did not jeopardize CpG-C-induced IL-12 response nor resistance to CT-26 metastases. Interestingly, attenuating glucocorticoid signaling under tilt&light conditions improved CpG-C efficacy. Overall, these findings suggest that perioperative hypothermic stress can jeopardize anti-metastatic immunity and resistance to metastasis, and prevent perioperative response to immune stimulation and its beneficial anti-metastatic impacts, effects that are not mediated through classical neuroendocrine stress responses, but potentially through direct hypothermic impact on leukocytes. These findings may have clinical implications in operated cancer patients, many of whom suffer hypothermic stress.

Development and optimization of a diluted whole blood ELISpot assay to test immune function

Sepsis remains a leading cause of death worldwide with no proven immunomodulatory therapies. Stratifying Patient Immune Endotypes in Sepsis (‘SPIES’) is a prospective, multicenter observational study testing the utility of ELISpot as a functional bioassay specifically measuring cytokine-producing cells after stimulation to identify the immunosuppressed endotype, predict clinical outcomes in septic patients, and test potential immune stimulants for clinical development. Most ELISpot protocols call for the isolation of PBMC prior to their inclusion in the assay. In contrast, we developed a diluted whole blood (DWB) ELISpot protocol that has been validated across multiple laboratories. Heparinized whole blood was collected from healthy donors and septic patients and tested under different stimulation conditions to evaluate the impact of blood dilution, stimulant concentration, blood storage, and length of stimulation on ex vivo IFNγ and TNFα production as measured by ELISpot. We demonstrate a dynamic range of whole blood dilutions that give a robust ex vivo cytokine response to stimuli. Additionally, a wide range of stimulant concentrations can be utilized to induce cytokine production. Further modifications demonstrate anticoagulated whole blood can be stored up to 24 h at room temperature without losing significant functionality. Finally, we show ex vivo stimulation can be as brief as 4 h allowing for a substantial decrease in processing time. The data demonstrate the feasibility of using ELISpot to measure the functional capacity of cells within DWB under a variety of stimulation conditions to inform clinicians on the extent of immune dysregulation in septic patients.

The treatment of psoriasis via herbal formulation and nano-polyherbal formulation: A new approach

Psoriasis is a chronic condition that can strike at any age. This sickness is associated with inflammatory problems that impact all humans in the world. Psoriasis is more common in Scandinavians than in Asian and African populations due to a combination of factors such as age, gender, geographic location, ethnicity, genetic and environmental factors. Immune stimulation, genetic contribution, antimicrobial peptides, and other significant triggers such as medicines, immunizations, infections, trauma, stress, obesity, alcohol intake, smoking, air pollution, sun exposure, and particular disorders cause psoriasis. Numerous clinical research investigations are now underway, and therapeutic alternatives are available. However, these therapies only improve symptoms and do not accomplish a complete cure; they also have dangerous and undesirable side effects. Natural products have gained popularity recently due to their great effectiveness, safety, and low toxicity. Natural formulations of various nanocarriers like liposomes, lipospheres, nanogels, emulgel, nanostructured lipid carriers, nanosponge, nanofibers, niosomes, nanomiemgel, nanoemulsions, nanospheres, cubosomes, microneedles, nanomicelles, ethosomes, nanocrystals, and foams, have significantly contributed and encouraged advancement in psoriasis disease treatment. These phytochemical-loaded new nanoformulations address several issues associated with natural products in conventional dosage forms, such as instability, poor solubility, and limited bioavailability. This article reviews some of the intriguing phytochemicals, as well as their possible molecular target locations and mechanisms of action, which may assist in the development of more specific and selective antipsoriatic medicines. Exploring and understanding phytochemicals' functions will allow for more site-specific psoriasis treatment techniques. This review concluded the psoriasis disease with phytoconstituent loaded herbal or polyherbal nanocarriers and their mechanistic approach.

Metal ions-anchored bacterial outer membrane vesicles for enhanced ferroptosis induction and immune stimulation in targeted antitumor therapy

The activation of ferroptosis presents a versatile strategy for enhancing the antitumor immune responses in cancer therapy. However, developing ferroptosis inducers that combine high biocompatibility and therapeutic efficiency remains challenging. In this study, we propose a novel approach using biological nanoparticles derived from outer membrane vesicles (OMVs) of Escherichia coli for tumor treatment, aiming to activate ferroptosis and stimulate the immune responses. Specifically, we functionalize the OMVs by anchoring them with ferrous ions via electrostatic interactions and loading them with the STING agonist-4, followed by tumor-targeting DSPE-PEG-FA decoration, henceforth referred to as OMV/SaFeFA. The anchoring of ferrous ions endows the OMVs with peroxidase-like activity, capable of inducing cellular lipid peroxidation by catalyzing H2O2 to •OH. Furthermore, OMV/SaFeFA exhibits pH-responsive release of ferrous ions and the agonist, along with tumor-targeting capabilities, enabling tumor-specific therapy while minimizing side effects. Notably, the concurrent activation of the STING pathway and ferroptosis elicits robust antitumor responses in colon tumor-bearing mouse models, leading to exceptional therapeutic efficacy and prolonged survival. Importantly, no acute toxicity was observed in mice receiving OMV/SaFeFA treatments, underscoring its potential for future tumor therapy and clinical translation.

Enhanced immunogenic response of salmonids to Tenacibaculum maritimum formalin-killed vaccine at different water temperatures

Tenacibaculum maritimum is the main organism responsible for yellow mouth (YM) and the primary driver for the use of antibiotics in Canadian Atlantic salmon culture. This creates a potential for the generation of antibiotic-resistant strains and brings significant costs to aquaculture producers. YM only occurs in Atlantic salmon recently transferred to saltwater, wherein affected fish die rapidly with few clinical signs apart from small yellow plaques around the mouth. Interestingly, if fish survive the first three to four months following saltwater transfer, they appear to have long-lasting protection against YM suggesting that immune memory may play a role. As a result, this costly predicament might be solved with an intervention that induces proper immune stimulation prior to the transfer of smolts to saltwater. To explore this, the current study developed an indirect ELISA that was specific for both Atlantic salmon and rainbow trout serum-IgM production towards a North American strain of T. maritimum. This assay was then used to confirm that Atlantic salmon routinely cultured in sea pens develop T. maritimum specific serum IgM and that this antibody development significantly increases over 220 days. To determine whether this antibody production could be induced and possibly optimized, a formalin inactivated T. maritimum vaccine was developed and used for intraperitoneal vaccinations of naïve rainbow trout while being maintained at low (11 °C) and high (15 °C) water temperatures. Analysis of leukocyte recruitment to the injection site revealed that the vaccine significantly enhanced total leukocyte and specifically lymphocyte recruitment when fish were held at the higher water temperature. Pathogen-specific antibody development was also significantly enhanced by the higher water temperature 21 days after receiving the vaccine. However, when a booster was given at day 21, any temperature-related differences in T. maritimum antibody levels between vaccinated groups was eliminated. A better understanding of salmonid antibody development towards T. maritimum could provide valuable insight into the development of an effective vaccine to prevent YM. Such a vaccine intervention could replace currently used antibiotic treatments and drastically improve the sustainability of North American aquaculture.

Antigen specificity affects analysis of natural antibodies.

Natural antibodies are used to compare immune systems across taxa, to study wildlife disease ecology, and as selection markers in livestock breeding. These immunoglobulins are present prior to immune stimulation. They are described as having low antigen specificity or polyreactive binding and are measured by binding to self-antigens or novel exogenous proteins. Most studies use only one or two antigens to measure natural antibodies and ignore potential effects of antigen specificity in analyses. It remains unclear how different antigen-specific natural antibodies are related or how diversity among natural antibodies may affect analyses of these immunoglobulins. Using genetically distinct lines of chickens as a model system, we tested the hypotheses that (1) antigen-specific natural antibodies are independent of each other and (2) antigen specificity affects the comparison of natural antibodies among animals. We used blood cell agglutination and enzyme-linked immunosorbent assays to measure levels of natural antibodies binding to four antigens: (i) rabbit erythrocytes, (ii) keyhole limpet hemocyanin, (iii) phytohemagglutinin, or (iv) ovalbumin. We observed that levels of antigen specific natural antibodies were not correlated. There were significant differences in levels of natural antibodies among lines of chickens, indicating genetic variation for natural antibody production. However, line distinctions were not consistent among antigen specific natural antibodies. These data show that natural antibodies are a pool of relatively distinct immunoglobulins, and that antigen specificity may affect interpretation of natural antibody function and comparative immunology.

Interpretable single-cell factor decomposition using sciRED.

Single-cell RNA sequencing (scRNA-seq) maps gene expression heterogeneity within a tissue. However, identifying biological signals in this data is challenging due to confounding technical factors, sparsity, and high dimensionality. Data factorization methods address this by separating and identifying signals in the data, such as gene expression programs, but the resulting factors must be manually interpreted. We developed Single-Cell Interpretable Residual Decomposition (sciRED) to improve the interpretation of scRNA-seq factor analysis. sciRED removes known confounding effects, uses rotations to improve factor interpretability, maps factors to known covariates, identifies unexplained factors that may capture hidden biological phenomena and determines the genes and biological processes represented by the resulting factors. We apply sciRED to multiple scRNA-seq datasets and identify sex-specific variation in a kidney map, discern strong and weak immune stimulation signals in a PBMC dataset, reduce ambient RNA contamination in a rat liver atlas to help identify strain variation, and reveal rare cell type signatures and anatomical zonation gene programs in a healthy human liver map. These demonstrate that sciRED is useful in characterizing diverse biological signals within scRNA-seq data.

Nanohybrid-Based Redox Homeostasis Perturbators Escaped from Early Lysosomes toward Amplified Sensitization of Tumor Cells and Photothermally Maneuvered Pyroptosis Therapy.

Reactive oxygen species (ROS) hold great potential in tumor pyroptosis therapy, yet they are still limited by short species lifespan and limited diffusion distance. Inducing cells into a metastable state and then applying external energy can effectively trigger pyroptosis, but systemic sensitization still faces challenges, such as limited ROS content, rapid decay, and short treatment windows. Herein, a nanohybrid-based redox homeostasis-perturbator system was designed that synergistically induce early lysosomal escape, autophagy inhibition, and redox perturbation functions to effectively sensitize cells to address these challenges. Specifically, weakly alkaline layered double hydroxide nanosheets (LDH NSs) with pH-responsive degradation properties enabled early lysosomal escape within 4 h, releasing poly(L-dopa) nanoparticles for inducing catechol-quinone redox cycling in the cytoplasm. The intracellular ROS levels were systematically rebounded by 3-4 times in tumor cells and lasted for over 4 h. Subsequently induced lysosomal stress and Ca2+ signaling activation resulted in severe mitochondrial dysfunction, as well as a perilous metastable state. Thereby, sequential near-infrared light was applied to trigger amplified stress through a local photothermal conversion. This led to sufficiently high levels of cleaved caspase-1 and GSDMD activation (2.5-2.8-fold increment) and subsequent pyroptosis response. In addition, OH- released by LDH elevated pH to alleviate the limitation of glutathione depletion by quinones at acidic pH and inhibit protective autophagy. Largely secreted inflammatory factors (2.5-5.6-fold increment), efficient maturation of dendritic cells, and further immune stimulation were boosted for tumor inhibition as a consequence. This study offers a new paradigm and insights into the synergy of internal systematic cellular sensitization and sequential external energy treatment to achieve tumor suppression through pyroptosis.

Interpretable single-cell factor decomposition using sciRED.

Single-cell RNA sequencing (scRNA-seq) maps gene expression heterogeneity within a tissue. However, identifying biological signals in this data is challenging due to confounding technical factors, sparsity, and high dimensionality. Data factorization methods address this by separating and identifying signals in the data, such as gene expression programs, but the resulting factors must be manually interpreted. We developed Single-Cell Interpretable Residual Decomposition (sciRED) to improve the interpretation of scRNA-seq factor analysis. sciRED removes known confounding effects, uses rotations to improve factor interpretability, maps factors to known covariates, identifies unexplained factors that may capture hidden biological phenomena and determines the genes and biological processes represented by the resulting factors. We apply sciRED to multiple scRNA-seq datasets and identify sex-specific variation in a kidney map, discern strong and weak immune stimulation signals in a PBMC dataset, reduce ambient RNA contamination in a rat liver atlas to help identify strain variation, and reveal rare cell type signatures and anatomical zonation gene programs in a healthy human liver map. These demonstrate that sciRED is useful in characterizing diverse biological signals within scRNA-seq data.

OST-HER2 Shows Positive Data in Phase 1 Clinical Trial of HER2-expressing Solid Tumors

OST-HER2, a biologic therapeutic candidate being developed by OS Therapies, is a Listeriamonocytogenes (Lm-) vector-based off-the-shelf immunotherapeutic vaccine designed to prevent metastasis, delay recurrence, and increase overall survival in patients with osteosarcoma and other solid tumors. The proposed OST-HER2 mechanism of action is based on innate and adaptive immune stimulating responses activated by the Lm vector. This treatment generates T-cells that can eliminate or slow potential micrometastases that can grow into recurrent osteosarcoma and other solid tumors, including breast cancer.

Differential Age-Based Response Induced by a Commercial Probiotic Supplementation in Pastured Goats.

The potential benefit of probiotics in small ruminant production systems has largely been unexplored. We evaluated the effect of a goat commercial probiotic on health and performance indicators in pastured goats from birth until 10months. We randomly allocated 26 newborn nursing goat kids to two groups: a control group that received saline and a treatment group that received a commercial probiotic paste orally. We evaluated select observable health indicators (inappetence, diarrhea, coughing), weight, immunity (IgA, IgG, and innate immune response), total protein, hematocrit (HCT), total lactic acid bacteria (LAB), total coliforms, and prevalence of Escherichia coli (E. coli) primary virulence genes (stx1, stx2, and eae) during the experimental period. The results revealed no significant differences in the health indicators, LAB count, and total E. coli count. Prevalence of stx1 at 1week of age and both stx1 and stx2 genes 4months post-weaning was significantly (P < 0.05) higher in probiotic-supplemented goats. Probiotic supplementation significantly (P < 0.05) increased the total protein and IgA 1month post-supplementation during the pre-weaning period and innate immune markers 2days post-weaning. The HCT in probiotic-supplemented goats was significantly (P < 0.05) higher at 1 and 2months post-weaning. The growth rate was not affected by probiotic supplementation in pre- and peri-weaned goats but was significantly (P < 0.05) lowered in goats older than 4months in the supplemented group. In this pastured goat production study, there were mixed responses to a commercial probiotic in healthy goats based on age. The study suggests that early daily probiotic supplementation in pre-weaned pastured goats may have immune stimulation benefits, but in older healthy animals, post-weaning net benefits are unclear and further research is recommended.

Nutritional Aspects for Modulation of Poultry Immune Stimulation

The immune system's defense mechanism has been affected by the management and nutrition conditions in poultry production. In biological aspects, Bursa Fabricius and Thymus are primary lymphoid organs that defend the body against diseases. The spleen, cecal tonsils, immunoglobulins, and various forms of mucosal immunity, BALT (bronchus-associated lymphoid tissue), MALT (mucosa-associated lymphoid tissue), CALT (conjunctiva-associated lymphoid tissue), and GALT (gut-associated lymphoid tissue), are also vital to their overall health. The management program (environmental conditions, heating, lighting practices) and nutritional supplementation (feed ingredients, composition, and feed additives) significantly affect birds' immunity and performance. Dietary supplementation enhances immune system activation by improving the lymphoid tissues and beneficial immune modulators and responses. During the past fifteen years, alternative feed additives (amino acids, minerals, vitamins, probiotics, prebiotics) have impacted animal production performance and immunity. Besides, feed additives, such as probiotics, prebiotics, vitamins, minerals, and organic acids, are essential for sustaining hormonal, physiological, and immunological processes. These additives, probiotics, vitamins (A, C, D, E), mineral (selenium) supplementations, and organic acids boost the immune system's activity against microbial pathogens and physiological stress mechanisms. At the last point, this paper aims to review the current improvement in the relationship between nutrition and immunity in poultry.

Investigating the Immune-Stimulating Potential of β-Glucan from Aureobasidium pullulans in Cancer Immunotherapy.

β-glucan, a polysaccharide found in various sources, exhibits unique physicochemical properties, yet its high polymerization limits clinical applications because of its solubility. Addressing this limitation, we introduce PPTEE-glycan, a highly purified soluble β-1,3/1,6-glucan derived from Aureobasidium pullulans. The refined PPTEE-glycan demonstrated robust immune stimulation in vitro, activated dendritic cells, and enhanced co-stimulatory markers, cytokines, and cross-presentation. Formulated as a PPTEE + microemulsion (ME), it elevated immune responses in vivo, promoting antigen-specific antibodies and CD8+ T cell proliferation. Intratumoral administration of PPTEE + ME in tumor-bearing mice induced notable tumor regression, which was linked to the activation of immunosuppressive cells. This study highlights the potential of high-purity Aureobasidium pullulans-derived β-glucan, particularly PPTEE, as promising immune adjuvants, offering novel avenues for advancing cancer immunotherapy.

Bioactivities and Structure-Activity Relationships of Usnic Acid Derivatives: A Review.

Usnic acid has a variety of biological activities, and has been widely studied in the fields of antibacterial, immune stimulation, antiviral, antifungal, anti-inflammatory and antiparasitic. Based on this, usnic acid is used as the lead compound for structural modification. In order to enhance the biological activity and solubility of usnic acid, scholars have carried out a large number of structural modifications, and found some usnic acid derivatives to be of more potential research value. In this paper, the structural modification, biological activity and structure-activity relationship of usnic acid were reviewed to provide reference for the development of usnic acid derivatives.

Immunomodulatory properties of chicken cathelicidin-2 investigated on an ileal explant culture.

As the threat posed by antimicrobial resistance grows more crucial, the development of compounds that can replace antibiotics becomes increasingly vital. Chicken cathelicidin-2 (Cath-2) belongs to the group of Host Defense Peptides (HDPs), which could provide a feasible solution for the treatment of gastrointestinal infections in poultry. It is a small peptide produced by the heterophil granulocytes of chickens as part of the innate immune response, and its immunomodulatory activity has already been demonstrated in several cell types. In this study, the effects of Cath-2 on the intestinal immune response were examined using ileal explant cultures isolated from chicken. Regarding our results, Cath-2 displayed a potent anti-inflammatory effect as it alleviated the LTA-caused elevation of interleukin (IL)-6 and IL-2 concentrations, and that of the IFN-γ/IL-10 ratio, furthermore, it increased the concentration of IL-10, alleviating the LTA-evoked decreased level of the anti-inflammatory cytokine. Moreover, when applied alone, it elevated the concentrations of IL-6, CXCLi2, and IL-2, providing evidence of its complex immunomodulatory mechanisms. In summary, Cath-2 was able to modulate the immune response of the intestinal wall not only by reducing pro-inflammatory cytokine release, but also through immune stimulation, demonstrating that it has the ability to improve innate immunity via a complex mechanism that may make it a suitable candidate for the control of intestinal infections.

Low-Molecular Weight Branched Polyethylenimine Reduces Cytokine Secretion from Human Immune System Monocytes Stimulated with Bacterial and Fungal PAMPs.

The innate immune system is an evolutionarily conserved pathogen recognition mechanism that serves as the first line of defense against tissue damage or pathogen invasion. Unlike the adaptive immunity that recruits T-cells and specific antibodies against antigens, innate immune cells express pathogen recognition receptors (PRRs) that can detect various pathogen-associated molecular patterns (PAMPs) released by invading pathogens. Microbial molecular patterns, such as lipopolysaccharide (LPS) from Gram-negative bacteria, trigger signaling cascades in the host that result in the production of pro-inflammatory cytokines. LPS stimulation produces a strong immune response and excessive LPS signaling leads to dysregulation of the immune response. However, dysregulated inflammatory response during wound healing often results in chronic non-healing wounds that are difficult to control. In this work, we present data demonstrating partial neutralization of anionic LPS molecules using cationic branched polyethylenimine (BPEI). The anionic sites on the LPS molecules from Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the lipid A moiety and BPEI binding create steric factors that hinder the binding of PRR signaling co-factors. This reduces the production of pro-inflammatory TNF-α cytokines. However, the anionic sites of Pseudomonas aeruginosa (P. aeruginosa) LPS are in the O-antigen region and subsequent BPEI binding slightly reduces TNF-α cytokine production. Fortunately, BPEI can reduce TNF-α cytokine expression in response to stimulation by intact P. aeruginosa bacterial cells and fungal zymosan PAMPs. Thus low-molecular weight (600 Da) BPEI may be able to counter dysregulated inflammation in chronic wounds and promote successful repair following tissue injury.

Enhanced Intratumoral Delivery of Immunomodulator Monophosphoryl Lipid A through Hyperbranched Polyglycerol–Coated Biodegradable Nanoparticles

Immunomodulatory agents (IMA) have significant potential to enhance cancer treatment but have demonstrated limited efficacy beyond the preclinical setting due to poor pharmacokinetics and toxicity associated with systemic administration. On the other hand, when locally delivered, IMAs require repeated administration to optimize immune stimulation. To overcome these challenges, we encapsulated the toll-like receptor (TLR)4 agonist monophosphoryl lipid A (MPLA) within hyperbranched polyglycerol (HPG)-coated biodegradable nanoparticles (NP) engineered for gradual drug release from the nanoparticle core, resulting in a more persistent stimulation of anti-tumor immune responses while minimizing systemic side effects. In a model of malignant melanoma, we demonstrate that HPG-NP encapsulation significantly improves the antitumor efficacy of MPLA by enhancing its ability to remodel the tumor microenvironment (TME). Compared to free MPLA, HPG-NP-MPLA significantly increased the natural killer cell and cytotoxic T cell mediated antitumor immune response and tuned the tumor draining lymph nodes towards a T helper (Th)1 response. Furthermore, when combined with local delivery of a chemotherapeutic agent, HPG-NP-MPLA induces the conversion of an immunosuppressive TME to immunogenic TME and significantly improves survival.

A DNA-Modularized STING Agonist with Macrophage-Selectivity and Programmability for Enhanced Anti-Tumor Immunotherapy.

The activation of cyclic GMP-AMP (cGAMP) synthase (cGAS) and its adaptor, stimulator of interferon genes (STING), is known to reprogram the immunosuppressive tumor microenvironment for promoting antitumor immunity. To enhance the efficiency of cGAS-STING pathway activation, macrophage-selective uptake, and programmable cytosolic release are crucial for the delivery of STING agonists. However, existing polymer- or lipid-based delivery systems encounter difficulty in integrating multiple functions meanwhile maintaining precise control and simple procedures. Herein, inspired by cGAS being a natural DNA sensor, a modularized DNA nanodevice agonist (DNDA) is designed that enable macrophage-selective uptake and programmable activation of the cGAS-STING pathway through precise self-assembly. The resulting DNA nanodevice acts as both a nanocarrier and agonist. Upon local administration, it demonstrates the ability of macrophage-selective uptake, endosomal escape, and cytosolic release of the cGAS-recognizing DNA segment, leading to robust activation of the cGAS-STING pathway and enhanced antitumor efficacy. Moreover, DNDA elicits a synergistic therapeutic effect when combined with immune checkpoint blockade. The study broadens the application of DNA nanotechnology as an immune stimulator for cGAS-STING activation.

Multifunctional Bispecific Nanovesicles Targeting SLAMF7 Trigger Potent Antitumor Immunity.

The effectiveness of immune checkpoint inhibitor (ICI) therapy is hindered by the ineffective infiltration and functioning of cytotoxic T cells and the immunosuppressive tumor microenvironment (TME). Signaling lymphocytic activation molecule family member 7 (SLAMF7) is a pivotal co-stimulatory receptor thought to simultaneously trigger NK-cell, T-cell, and macrophage antitumor cytotoxicity. However, the potential of this collaborative immune stimulation in antitumor immunity for solid tumors is underexplored due to the exclusive expression of SLAMF7 by hematopoietic cells. Here, we report the development and characterization of multifunctional bispecific nanovesicles (NVs) targeting SLAMF7 and glypican-3-a hepatocellular carcinoma (HCC)-specific tumor antigen. We found that by effectively "decorating" the surfaces of solid tumors with SLAMF7, these NVs directly induced potent and specific antitumor immunity and remodeled the immunosuppressive TME, sensitizing the tumors to programmed cell death protein 1 (PD1) blockade. Our findings highlight the potential of SLAMF7-targeted multifunctional bispecific NVs as an anticancer strategy with implications for designing next-generation targeted cancer therapies.

Immunomodulatory activity of polycaprolactone nanoparticles with calcium phosphate salts against Leishmania infantum infection

Objective: To prepare and characterize polycaprolactone (PCL) nanoparticles loaded with sonicator fragmented (SLA) and freeze- thaw Leishmania antigens (FTLA) and to investigate the in vitro immunogenicity of antigen-encapsulated nanoparticles with calcium phosphate adjuvant. Methods: The water/oil/water binary emulsion solvent evaporation method was used to synthesize antigen-loaded PCL nanoparticles. Particles were characterized by scanning electron microscopy and zeta potential measurements. Their cytotoxicity in J774 macrophages in vitro was determined by MTT analysis. In addition, the amount of nitric oxide and the level of cytokines produced by macrophages were determined by Griess reaction and ELISA method, respectively. The protective effect of the developed formulations was evaluated by determining the infection index percentage in macrophages infected with Leishmania infantum. Results: Compared to the control group, SLA PCL and FTLA PCL nanoparticles with calcium phosphate adjuvant induced a 6- and 7-fold increase in nitric oxide, respectively. Additionally, the vaccine formulations promoted the production of IFN-γ and IL-12. SLA PCL and FTLA PCL nanoparticles combined with calcium phosphate adjuvant caused an approximately 13- and 11-fold reduction in infection index, respectively, compared to the control group. Conclusions: The encapsulation of antigens obtained by both sonication and freeze-thawing into PCL nanoparticles and the formulations with calcium phosphate adjuvant show strong in vitro immune stimulating properties. Therefore, PCL-based antigen delivery systems and calcium phosphate adjuvant are recommended as a potential vaccine candidate against leishmaniasis.