Prophylactic Setting Research Articles

Level of expression of MHCI-presented neoepitopes influences tumor rejection by neoantigen-specific CD8+ T cells.

Neoantigen-targeted therapy holds an array of benefits for cancer immunotherapy, but the identification of peptide targets with tumor rejection capacity remains a limitation. To better define the criteria dictating tumor rejection potential, we examined the capacity of high-magnitude T cell responses induced towards several distinct neoantigen targets to regress MC38 tumors. Surprisingly, despite their demonstrated immunogenicity, vaccine-induced T-cell responses were unable to regress established MC38 tumors or prevent tumor engraftment in a prophylactic setting. However, T cells were functional with robust killing capacity towards neoantigen peptide-loaded cells. Furthermore, tumor cell killing was rescued in proportion to the expression level or saturation of target peptide-loaded MHCs on the cell surface. Overall, this study demonstrates a pivotal role for target protein expression levels in modulating the tumor rejection capacity of neoantigens. Thus, inclusion of this metric, in addition to immunogenicity analysis, may benefit antigen prediction techniques to ensure the full anti-tumor effect of cancer vaccines.

ThP3.3 - Prophylactic Endoluminal Vacuum Therapy – towards an era of reducing leak related morbidity after elective oesophago-gastric resection

Abstract Aims Uncontrolled sepsis following leak from oesophago-gastric surgery is a devastating condition with increased morbidity & mortality affecting longer-term cancer-free survival in patients with cancer resections. We hypothesised that endoluminal vacuum therapy (EVT), previously used to treat leaks, could be used in prophylactic settings to provide source-control, prevent mediastinitis and minimise sepsis related morbidity from leaks. Methods An ad-hocEVT device was created using VACgranufoam (KCI)and a nasogastric-tube(16/18Fr), and placed intraluminally across the repair/anastomosis in select high-risk cases. Continuous negative pressure(75–125mmHg) was applied. Assessment of the repair-site/anastomosis was performed by radiology, endoscopy, clinical assessment or a combination following cessation of EVT. Results 27 patients had prophylactic EVT; M:F ratio was 3:1 and the median age was 68 years (range: 41-82years). 26surgeries were for cancer, while 1 was benign. The rationale for prophylactic EVT included patient related (10), technical factors (16) or both (1). The median duration of prophylactic EVT was 7 days (range: 4-14days). The median length-of-stay was 19.7 days (range: 6-96 days), the two longest admissions were unrelated to the anastomosis(prolonged chyle-leak, and long-term-sequelae of life-threatening bleed). One-patient developed a full-thickness microleak at endoscopic-evaluation, yet remained well with no systemic signs of sepsis, successfully managed with luminalEVT for a further 6days in a ward-based environment. Though prophylacticEVT did not prevent the leak, it significantly minimised the systemic hit that traditionally results from leak and associated mediastinal sepsis. Conclusions ProphylacticEVT is a useful adjunct for management of patients with a high risk for leak, though not a substitute for good surgical technique. There are no short-term complications, yet the additional morbidity, mortality and length-of-stay associated with a fully-fledged leak is avoided. Randomised-controlled-trials are required to further standardise selection criteria, assess potential patient benefit and longer-term impact on survivorship.

40 Preclinical evaluation of a novel dendritic cell vaccine for kidney cancer

Abstract Background Dendritic cell (DC)-based vaccines have been previously shown to promote therapeutic T cell responses in both preclinical tumor models and in cancer patients, where extended patient overall survival has been noted in many cases. The goal of the present study is to develop a novel DC-based vaccine as an effective immuno-oncology (IO) agent for the prevention/treatment of kidney cancer. We previously demonstrated that actin-binding protein profilin1 (Pfn1) is overexpressed in tumor-associated vascular endothelial cells (ECs), where it may serve as a prognostic factor in human clear cell renal cancer (ccRCC). We further established a direct causal relationship between EC Pfn1 dysregulation, immune microenvironment alterations, and tumor progression in mouse models of RCC. The current work specifically explores whether Pfn1-targeted DC-based vaccines are effective in preventing orthotopic RCC in mice. Methods To generate Pfn1-targeted DC vaccines, we harvested and matured DCs from Balb/C mouse bone marrow-derived precursor cells in cultures containing rmIL4 and rmGM-CSF. DCs loaded with individual Pfn1 synthetic peptides (these sequences were identified using three MHC class I/II peptide-binding algorithms) were injected into syngeneic mice on days 0, 7 and 14. Spleens were harvested from immunized mice on day 21 to isolate CD4+ and CD8+ T cells, with T cells then stimulated with unmanipulated DCs or DCs pulsed with individual immunizing peptides to detect specific T cell activation, as measured by IFN-gamma release quantitated by ELISA. Tissue histology was performed to assess immune-related adverse events (iRAE) in vaccinated mice as a safety index. For cancer studies, Balb/c mice were immunized with DCs loaded with pooled Pfn1 peptides a few days prior to establishing either subcutaneous or orthotopic RCC tumors. Tumor-bearing mice were subjected to an identical booster vaccine prior one week later in advance of euthanasia and study end-point analyses. Results Our studies show that vaccination of Balb/c mice with DCs pulsed with Pfn1 peptides elicit specific CD4+ and/or CD8+ T cell responses without promoting irAEs. When applied in the prophylactic setting, DC-Pfn1 peptide vaccines substantially slow the growth of subcutaneous RCC tumors. In support of these findings, we have also developed preliminary data supporting the therapeutic effects of DC/Pfn1-peptide vaccines in a murine orthotopic model of RCC. Conclusions In summary, our studies provide first evidence for Pfn1-targeted IO agent in the cancer setting. Given that the survival benefit for dual immune-check point inhibitors (ICI)/anti-angiogenic therapy remains modest and is limited to a small minority of ccRCC patients, Pfn1-targeted vaccines could represent a novel therapeutic agent for improved patient outcomes when applied alone or in combination with in-clinic ICI agents. DOD CDMRP Funding: yes

Penicillin concentrations in bone and subcutaneous tissue: A porcine microdialysis study comparing oral and intravenous treatment.

Penicillin is available in both an oral (penicillin V) and intravenous formulation (penicillin G), theoretically allowing for a safe transition between the two. However, the use of oral penicillin remains a topic of debate due to low and variable bioavailability. This study aimed to assess the time for which the free penicillin concentration exceeded targeted minimum inhibitory concentrations for Staphylococcus aureus and Streptococcus species (0.125, 0.25, and 0.5 mg/L) in cancellous bone and subcutaneous tissue after intravenous penicillin and oral penicillin administration. 12 female pigs (68-75 kg) were assigned, according to local standard clinical regimes, to either intravenous penicillin (1.2 g) or oral penicillin (0.8 g) treatment every 6 h over an 18 h period. Microdialysis catheters were placed for sampling in tibial cancellous bone and adjacent subcutaneous tissue. Data was dynamic/continually collected in the first dosing interval (0-6 h), simulating a prophylactic situation, and the third dosing interval (12-18 h), simulating a therapeutic setting. Plasma samples were collected for reference. For all investigated targets, intravenous treatment resulted in a longer mean time above relevant minimum inhibitory concentrations in cancellous bone during the first dosing interval, and in both cancellous bone and subcutaneous tissue during the third dosing interval compared to oral treatment. With clinically relevant dosing, intravenous penicillin provides superior exposure compared to oral penicillin in both a prophylactic and therapeutic setting.

Prophylactic and therapeutic cancer vaccine with continuous localized immunomodulation

Selective in vivo immune cell manipulation offers a promising strategy for cancer vaccines. In this context, spatiotemporal control over recruitment of specific cells, and their direct exposure to appropriate immunoadjuvants and antigens are key to effective cancer vaccines. We present an implantable 3D-printed cancer vaccine platform called the ‘NanoLymph’ that enables spatiotemporally-controlled recruitment and manipulation of immune cells in a subcutaneous site. Leveraging two reservoirs each for continuous immunoadjuvant release or antigen presentation, the NanoLymph attracts dendritic cells (DCs) on site and exposes them to tumor-associated antigens. Upon local antigen-specific activation, DCs are mobilized to initiate a systemic immune response. NanoLymph releasing granulocyte-macrophage colony-stimulating factor and CpG-oligodeoxynucleotides with irradiated whole cell tumor lysate inhibited tumor growth of B16F10 murine melanoma in a prophylactic and therapeutic vaccine setting. Overall, this study presents the NanoLymph as a versatile cancer vaccine development platform with replenishable and controlled local release of antigens and immunoadjuvants.

Mixed effect estimation in deep compartment models: Variational methods outperform first-order approximations.

This work focusses on extending the deep compartment model (DCM) framework to the estimation of mixed-effects. By introducing random effects, model predictions can be personalized based on drug measurements, enabling the testing of different treatment schedules on an individual basis. The performance of classical first-order (FO and FOCE) and machine learning based variational inference (VI) algorithms were compared in a simulation study. In VI, posterior distributions of the random variables are approximated using variational distributions whose parameters can be directly optimized. We found that variational approximations estimated using the path derivative gradient estimator version of VI were highly accurate. Models fit on the simulated data set using the FO and VI objective functions gave similar results, with accurate predictions of both the population parameters and covariate effects. Contrastingly, models fit using FOCE depicted erratic behaviour during optimization, and resulting parameter estimates were inaccurate. Finally, we compared the performance of the methods on two real-world data sets of haemophilia A patients who received standard half-life factor VIII concentrates during prophylactic and perioperative settings. Again, models fit using FO and VI depicted similar results, although some models fit using FO presented divergent results. Again, models fit using FOCE were unstable. In conclusion, we show that mixed-effects estimation using the DCM is feasible. VI performs conditional estimation, which might lead to more accurate results in more complex models compared to the FO method.

CO-DELIVERY of glutamic acid-extended peptide antigen and imidazoquinoline TLR7/8 agonist via ionizable lipid nanoparticles induces protective anti-tumor immunity

Cancer vaccines aim at generating cytotoxic CD8+ T cells that kill cancer cells and confer durable tumor regression. Hereto, CD8+ peptide epitopes should be presented by antigen presenting cells to CD8+ T cells in lymphoid tissue. Unfortunately, in unformulated soluble form, peptide antigens are poorly taken up by antigen presenting cells and do not efficiently reach lymph nodes. Hence, the lack of efficient delivery remains a major limitation for successful clinical translation of cancer vaccination using peptide antigens. Here we propose a generic peptide nanoformulation strategy by extending the amino acid sequence of the peptide antigen epitope with 10 glutamic acid residues. The resulting overall anionic charge of the peptide allows encapsulation into lipid nanoparticles (peptide-LNP) by electrostatic interaction with an ionizable cationic lipid. We demonstrate that intravenous injection of peptide-LNP efficiently delivers the peptide to immune cells in the spleen. Peptide-LNP that co-encapsulate an imidazoquinoline TLR7/8 agonist (IMDQ) induce robust innate immune activation in a broad range of immune cell subsets in the spleen. Peptide-LNP containing the minimal CD8+ T cell epitope of the HPV type 16 E7 oncoprotein and IMDQ induces high levels of antigen-specific CD8+ T cells in the blood, and can confer protective immunity against E7-expressing tumors in both prophylactic and therapeutic settings.

Preclinical development of ATR04-484, an auxotrophic strain of Staphylococcus epidermidis, for the topical treatment of epidermal growth factor receptor (EGFR) inhibitor-induced dermal toxicity.

e24074 Background: Agents targeting the EGFR-mediated signaling pathway are commonly used for the treatment of advanced lung, pancreatic, colorectal, and head and neck cancers. Significant dermal toxicities, which occur in up to 90% of patients treated with EGFR inhibitors (EGFRis) and other therapies inhibiting downstream signaling pathways, may be disruptive to a patient’s quality of life and adherence to therapy. Inhibition of the EGFR pathway may suppress host defenses and lead to opportunistic pathogenic colonization or infection. EGFRi-induced dermal toxicity is associated with elevated levels of Staphylococcus aureus and IL-36γ. ATR04-484 is a topical ointment containing S. epidermidis strain SE484, isolated from a healthy human volunteer that was selected for its ability to inhibit S. aureus and IL-36γ . Methods: Reconstructed human epidermis (RHE) and ex vivo pig skin were used to measure the effect of ATR04-484 on S. aureus in therapeutic and prophylactic settings with S. aureus added prior to or after ATR04-484, respectively. To evaluate the anti-inflammatory effects of ATR04-484, IL-36γ levels were measured on untreated RHE and RHE treated with erlotinib alone or in combination with ATR04-484. 104 colony-forming units (CFU) of methicillin-resistant (MRSA) or methicillin-sensitive (MSSA) S. aureus were used. Toxicology was assessed by measuring cell viability in three in vitro toxicology assays: the eye irritant potential was tested on 3D reconstituted human cornea-like epithelium (RhCE), the skin irritant potential of the strain in the ointment was assessed on 3D RHE, and the skin corrosive potential was evaluated on RHE. Results: ATR04-484 comparably inhibited growth of both MRSA and MSSA in therapeutic and prophylactic settings. In a therapeutic setting, ATR04-484 inhibited MRSA growth by 1 log (90%) compared to untreated MRSA in both RHE and pig skin. In a prophylactic setting, ATR04-484 inhibited MRSA growth by approximately 5 logs on RHE and 2 logs on pig skin. Additionally, application of ATR04-484 reduced IL-36γ to a level comparable to untreated RHE. The effect was dose-dependent; application of 109CFU/cm2 of ATR04-484 showed more potent IL-36γ reduction compared to 108 CFU/cm2. The three toxicology assays indicate that ATR04-484 does not cause irritation or corrosion. Conclusions: In these preclinical studies, ATR-04-484 showed a promising preclinical profile for the treatment of EGFRi-induced dermal toxicity by significantly reducing S. aureus growth, completely ameliorating IL-36γ levels, and showing no safety concerns.

Prophylactic slowly resorbable mesh in midline laparotomy to limit incisional hernia incidence: the prospective ‘Mesh Augmented Reinforcement of Abdominal Wall Suture Line (MARS)’ cohort study protocol

Background: Incisional hernia (IH) after abdominal surgery is a frequent surgical complication. Risk factors associated with IH are midline incisions, patients with an abdominal aneurysm of the aorta, and high BMI. Preventive measures include the use of the small-bites suture technique and/or placing a prophylactic mesh for reinforcement of the midline closure. Although recommended for high-risk patients, many surgeons are still reluctant to place a prophylactic mesh due to related complications. To counter these concerns, new synthetic resorbable meshes are being developed, such as the Deternia Self-Gripping Resorbable Mesh (“investigational device”). However, the effectiveness of this mesh in IH prevention has not been proved. Methods: The Mesh Augmented Reinforcement of Abdominal Wall Suture Line (MARS) study is a European, multicentre, prospective, single-arm study. A total of 120 patients scheduled for elective midline laparotomy, and for that reason at risk of developing IH, will be recruited in ~12 sites after informed consent. The sample size was estimated based on greater than 80% power, two-sided alpha of 0.05, an expected 12 month IH rate of 8% and a predefined performance goal of 18% (10% clinical margin). Midline incisions will be closed by the small bites closure technique with a minimum 4:1 suture-to-wound length ratio and reinforced by mesh placement in the retrorectus position. The primary outcome will be IH occurrence at 12-month postoperatively, evaluated both clinically and by ultrasound. Secondary outcomes will include mesh-related and postoperative complications, surgical characteristics, IH incidence at 2 and 3 years after surgery, and quality of life. Discussion: Currently, no conclusive evidence is available for synthetic resorbable meshes in a prophylactic setting to prevent IH. The MARS study will be the first prospective cohort study to investigate resorbable synthetic meshes and small bites closure to reduce IH incidence.

Ultrasoft platelet-like particles stop bleeding in rodent and porcine models of trauma.

Uncontrolled bleeding after trauma represents a substantial clinical problem. The current standard of care to treat bleeding after trauma is transfusion of blood products including platelets; however, donated platelets have a short shelf life, are in limited supply, and carry immunogenicity and contamination risks. Consequently, there is a critical need to develop hemostatic platelet alternatives. To this end, we developed synthetic platelet-like particles (PLPs), formulated by functionalizing highly deformable microgel particles composed of ultralow cross-linked poly (N-isopropylacrylamide) with fibrin-binding ligands. The fibrin-binding ligand was designed to target to wound sites, and the cross-linking of fibrin polymers was designed to enhance clot formation. The ultralow cross-linking of the microgels allows the particles to undergo large shape changes that mimic platelet shape change after activation; when coupled to fibrin-binding ligands, this shape change facilitates clot retraction, which in turn can enhance clot stability and contribute to healing. Given these features, we hypothesized that synthetic PLPs could enhance clotting in trauma models and promote healing after clotting. We first assessed PLP activity in vitro and found that PLPs selectively bound fibrin and enhanced clot formation. In murine and porcine models of traumatic injury, PLPs reduced bleeding and facilitated healing of injured tissue in both prophylactic and immediate treatment settings. We determined through biodistribution experiments that PLPs were renally cleared, possibly enabled by ultrasoft particle properties. The performance of synthetic PLPs in the preclinical studies shown here supports future translational investigation of these hemostatic therapeutics in a trauma setting.

Heterologous cAd3-Ebola and MVA-EbolaZ vaccines are safe and immunogenic in US and Uganda phase 1/1b trials

Ebola virus disease (EVD) is a filoviral infection caused by virus species of the Ebolavirus genus including Zaire ebolavirus (EBOV) and Sudan ebolavirus (SUDV). We investigated the safety and immunogenicity of a heterologous prime-boost regimen involving a chimpanzee adenovirus 3 vectored Ebola vaccine [either monovalent (cAd3-EBOZ) or bivalent (cAd3-EBO)] prime followed by a recombinant modified vaccinia virus Ankara EBOV vaccine (MVA-EbolaZ) boost in two phase 1/1b randomized open-label clinical trials in healthy adults in the United States (US) and Uganda (UG). Trial US (NCT02408913) enrolled 140 participants, including 26 EVD vaccine-naïve and 114 cAd3-Ebola-experienced participants (April-November 2015). Trial UG (NCT02354404) enrolled 90 participants, including 60 EVD vaccine-naïve and 30 DNA Ebola vaccine-experienced participants (February-April 2015). All tested vaccines and regimens were safe and well tolerated with no serious adverse events reported related to study products. Solicited local and systemic reactogenicity was mostly mild to moderate in severity. The heterologous prime-boost regimen was immunogenic, including induction of durable antibody responses which peaked as early as two weeks and persisted up to one year after each vaccination. Different prime-boost intervals impacted the magnitude of humoral and cellular immune responses. The results from these studies demonstrate promising implications for use of these vaccines in both prophylactic and outbreak settings.

Melanoma extracellular vesicles inhibit tumor growth and metastasis by stimulating CD8 T cells

Tumor cell-derived extracellular vesicles (EVs) play a crucial role in mediating immune responses by carrying and presenting tumor antigens. Here, we suggested that melanoma EVs triggered cytotoxic CD8 T cell-mediated inhibition of tumor growth and metastasis. Our results indicated that immunization of mice with melanoma EVs inhibited melanoma growth and metastasis while increasing CD8 T cells and serum interferon γ (IFN-γ) in vivo. In vitro experiments showed that melanoma EV stimulates dendritic cells (DCs) maturation, and mature dendritic cells induce T lymphocyte activation. Thus, tumor cell-derived EVs can generate anti-tumor immunity in a prophylactic setting and may be potential candidates for cell-free tumor vaccines.

OP33 Mechanistic insights on the role of ultra processed foods as a trigger/fuel for IBD

Abstract Background Ultra processed foods (UPFs) are a heterogeneous category of products that contain food additives and/or have undergone several industrial processes. The higher intake of UPFs seen in industrialized countries has been associated with increased incidence of inflammatory bowel diseases (IBD), mainly Crohn’s disease (CD). However, the specific mechanisms through which the UPFs can induce or maintain intestinal inflammation are still unknown. Therefore, most dietary interventions for IBD essentially exclude all UPFs from the menu, increasing the difficulty of long-term compliance of these diets. The main focus of my research is the study of which components may be detrimental in UPFs, in the hope that we can limit the number of UPFs that we need to exclude from our diets. Methods To understand the mechanism of action of UPFs, a translational approach is needed with complementary pre-clinical and clinical studies. We used organoid cultures from patients with CD to test the impact of food additives on the intestinal epithelium (e.g. permeability, pro-inflammatory effect). These organoid cultures are more physiologically relevant than immortalized cell lines, which lack several important aspects (e.g. genetic background, complex assembly of different cells). The results of the first tests with this platform have been submitted to ECCO (EC24-1418). Additionally, we established several protocols and collaborations to run well designed dietary intervention studies to explore the mechanisms of action of these food additives in humans. In the FOAM study, we explored the effects of 5 emulsifiers in an double blind randomized placebo controlled trial. The results of the FOAM study have also been submitted to ECCO (EC24-0858). We also explored the acceptance, feasibility, and compliance of an emulsifier free diet in healthy volunteers (EC24-1181). Results Our results support the need to better understand the role of food additives and UPFs in IBD, and the need for better evidence supporting the detrimental role of food additives. Conclusion Compliance is an important issue to consider in all dietary interventions, more than in pharmacological interventions. Strategies focusing on improving the compliance of dietary interventions can have a big impact in the applicability of these interventions in therapeutic and/or prophylactic settings. However, the current knowledge on the possible detrimental role of UPFs does not allow to pinpoint which UPFs are detrimental and which might have no effect on intestinal inflammation. Hence, there is an unmet need for pre-clinical and clinical studies focusing on the mechanisms through which these UPFs might play a role in intestinal inflammation.

Injectable Mesocellular Foam Silica Microparticles with a Dual Role of Cell‐Recruiting Scaffolds and Intracellular Delivery Vehicles for Enhanced Cancer Vaccine

AbstractThe cancer vaccine is one of the potent cancer immunotherapies based on provoking antigen‐specific adaptive immune responses in patients. Activating host antigen‐presenting cells by delivering antigens and adjuvants is one of the most important requirements to enhance cancer vaccine efficacy. This study proposes an effective cancer vaccine platform based on injectable mesocellular foam (MCF) silica microparticles with a dual role capable of in situ recruitment of host dendritic cells (DCs) and intracellular delivery of antigens to the recruited DCs. Subcutaneously administrated MCF microparticles loaded with chemoattractant to DCs (GM‐CSF), antigenic protein (OVA), and TLR9 agonist (CpG‐ODN) lead to robust DC maturation and high antigen‐specific T cell responses. The cell recruitment, DC activation, and T cell responses of MCF‐based cancer vaccine are significantly higher than injectable mesoporous silica scaffold, of which role is mostly limited to the cell recruiting scaffold. These features of MCF lead to effective inhibition of tumor growth in prophylactic vaccine setting and lung metastatic cancer model, representing MCF enabling cell‐recruiting scaffold formation and intracellular delivery of antigen can be a promising material platform for an enhanced cancer vaccine.

Mitigating radiation-induced cognitive toxicity in brain metastases: More questions than answers.

The emergence of advanced systemic therapies added to the use of cranial radiation techniques has significantly improved outcomes for cancer patients with multiple brain metastases (BM), leading to a considerable increase in long-term survivors. In this context, the rise of radiation-induced cognitive toxicity (RICT) has become increasingly relevant. In this critical narrative review, we address the controversies arising from clinical trials aimed at mitigating RICT. We thoroughly examine interventions such as memantine, hippocampal avoidance irradiation during BM treatment or ina prophylactic setting, and the assessment of cognitive safety in stereotactic radiosurgery (SRS). Our focus extends to recent neuroscience research findings, emphasizing the importance of preserving not only the hippocampal cortex but also other cortical regions involved in neural dynamic networks and their intricate role in encoding new memories. Despite treatment advancements, effectively managing patients with multiple BM and determining the optimal timing and integration of radiation and systemic treatments remain areas requiring further elucidation. Future trials are required to delineate optimal indications and ensure SRS safety. Additionally, the impact of new systemic therapies and the potential effects of delaying irradiation on cognitive functioning also need to be addressed. Inclusive trial designs, encompassing patients with multiple BM and accounting for diverse treatment scenarios, are essential for advancing effective strategies in managing RICT and the treatment of BM patients.

An ACE2 decamer viral trap as a durable intervention solution for current and future SARS-CoV

ABSTRACT The capacity of SARS-CoV-2 to evolve poses challenges to conventional prevention and treatment options such as vaccination and monoclonal antibodies, as they rely on viral receptor binding domain (RBD) sequences from previous strains. Additionally, animal CoVs, especially those of the SARS family, are now appreciated as a constant pandemic threat. We present here a new antiviral approach featuring inhalation delivery of a recombinant viral trap composed of ten copies of angiotensin-converting enzyme 2 (ACE2) fused to the IgM Fc. This ACE2 decamer viral trap is designed to inhibit SARS-CoV-2 entry function, regardless of viral RBD sequence variations as shown by its high neutralization potency against all known SARS-CoV-2 variants, including Omicron BQ.1, BQ.1.1, XBB.1 and XBB.1.5. In addition, it demonstrates potency against SARS-CoV-1, human NL63, as well as bat and pangolin CoVs. The multivalent trap is effective in both prophylactic and therapeutic settings since a single intranasal dosing confers protection in human ACE2 transgenic mice against viral challenges. Lastly, this molecule is stable at ambient temperature for more than twelve weeks and can sustain physical stress from aerosolization. These results demonstrate the potential of a decameric ACE2 viral trap as an inhalation solution for ACE2-dependent coronaviruses of current and future pandemic concerns.

Antiviral Potential of Azelastine against Major Respiratory Viruses.

The Coronavirus Disease 2019 (COVID-19) pandemic and the subsequent increase in respiratory viral infections highlight the need for broad-spectrum antivirals to enable a quick and efficient reaction to current and emerging viral outbreaks. We previously demonstrated that the antihistamine azelastine hydrochloride (azelastine-HCl) exhibited in vitro antiviral activity against SARS-CoV-2. Furthermore, in a phase 2 clinical study, a commercial azelastine-containing nasal spray significantly reduced the viral load in SARS-CoV-2-infected individuals. Here, we evaluate the efficacy of azelastine-HCl against additional human coronaviruses, including the SARS-CoV-2 omicron variant and a seasonal human coronavirus, 229E, through in vitro infection assays, with azelastine showing a comparable potency against both. Furthermore, we determined that azelastine-HCl also inhibits the replication of Respiratory syncytial virus A (RSV A) in both prophylactic and therapeutic settings. In a human 3D nasal tissue model (MucilAirTM-Pool, Epithelix), azelastine-HCl protected tissue integrity and function from the effects of infection with influenza A H1N1 and resulted in a reduced viral load soon after infection. Our results suggest that azelastine-HCl has a broad antiviral effect and can be considered a safe option against the most common respiratory viruses to prevent or treat such infections locally in the form of a nasal spray that is commonly available globally.

Evaluation of the Neutralizing Antibody STE90-C11 against SARS-CoV-2 Delta Infection and Its Recognition of Other Variants of Concerns.

As of now, the COVID-19 pandemic has spread to over 770 million confirmed cases and caused approximately 7 million deaths. While several vaccines and monoclonal antibodies (mAb) have been developed and deployed, natural selection against immune recognition of viral antigens by antibodies has fueled the evolution of new emerging variants and limited the immune protection by vaccines and mAb. To optimize the efficiency of mAb, it is imperative to understand how they neutralize the variants of concern (VoCs) and to investigate the mutations responsible for immune escape. In this study, we show the in vitro neutralizing effects of a previously described monoclonal antibody (STE90-C11) against the SARS-CoV-2 Delta variant (B.1.617.2) and its in vivo effects in therapeutic and prophylactic settings. We also show that the Omicron variant avoids recognition by this mAb. To define which mutations are responsible for the escape in the Omicron variant, we used a library of pseudovirus mutants carrying each of the mutations present in the Omicron VoC individually. We show that either 501Y or 417K point mutations were sufficient for the escape of Omicron recognition by STE90-C11. To test how escape mutations act against a combination of antibodies, we tested the same library against bispecific antibodies, recognizing two discrete regions of the spike antigen. While Omicron escaped the control by the bispecific antibodies, the same antibodies controlled all mutants with individual mutations.

Optimized dithranol-imiquimod-based transcutaneous immunization enables tumor rejection.

Transcutaneous immunization (TCI) is a non-invasive vaccination method promoting strong cellular immune responses, crucial for the immunological rejection of cancer. Previously, we reported on the combined application of the TLR7 agonist imiquimod (IMQ) together with the anti-psoriatic drug dithranol as novel TCI platform DIVA (dithranol/IMQ based vaccination). In extension of this work, we further optimized DIVA in terms of drug dose, application pattern and established a new IMQ formulation. C57BL/6 mice were treated on the ear skin with dithranol and IMQ-containing ointments together with ovalbumin-derived peptides. T cell responses were determined by flow cytometry and IFN-ɤ ELISpot assay, local skin inflammation was characterized by ear swelling. Applying the adjuvants on separate skin sites, a reduced number of specific CD8+ T cells with effector function was detectable, indicating that the local concurrence of adjuvants and peptide antigens is required for optimal vaccination. Likewise, changing the order of dithranol and IMQ resulted in an increased skin inflammatory reaction, but lower frequencies of antigen-specific CD8+ T cells indicating that dithranol is essential for superior T cell priming upon DIVA. Dispersing nanocrystalline IMQ in a spreadable formulation (IMI-Sol+) facilitated storage and application rendering comparable immune responses. DIVA applied one or two weeks after the first immunization resulted in a massive increase in antigen-specific T cells and up to a ten-fold increased memory response. Finally, in a prophylactic tumor setting, double but no single DIVA treatment enabled complete control of tumor growth, resulting in full tumor protection. Taken together, the described optimized transcutaneous vaccination method leads to the generation of a strong cellular immune response enabling the effective control of tumor growth and has the potential for clinical development as a novel non-invasive vaccination method for peptide-based cancer vaccines in humans.

Cancer Cell Membrane Nanodiscs for Antitumor Vaccination.

Cell membrane-based nanovaccines have demonstrated attractive features due to their inherently multiantigenic nature and ability to be formulated with adjuvants. Here, we report on cellular nanodiscs fabricated from cancer cell membranes and incorporated with a lipid-based adjuvant for antitumor vaccination. The cellular nanodiscs, with their small size and discoidal shape, are readily taken up by antigen-presenting cells and drain efficiently to the lymph nodes. Due to its highly immunostimulatory properties, the nanodisc vaccine effectively stimulates the immune system and promotes tumor-specific immunity. Using a murine colorectal cancer model, strong control of tumor growth is achieved in both prophylactic and therapeutic settings, particularly in combination with checkpoint blockades. Considerable therapeutic efficacy is also observed in treating a weakly immunogenic metastatic melanoma model. This work presents a new paradigm for the design of multiantigenic nanovaccines that can effectively activate antitumor immune responses and may be applicable to a wide range of cancers.