Dose-sparing Potential Research Articles

Displaying alphavirus physicochemical consensus antigens on immunogenic liposomes enhances antibody elicitation in mice

Cobalt-porphyrin phospholipid displays recombinant protein antigens on liposome surfaces via antigen polyhistidine-tag (His-tag), and when combined with monophosphorylated lipid A and QS-21 yields the “CPQ” vaccine adjuvant system. In this proof of principle study, CPQ was used to generate vaccine prototypes that elicited antibodies for two different alphaviruses (AV). Mice were immunized with computationally designed, His-tagged, physicochemical property consensus (PCPcon) protein antigens representing the variable B-domain of the envelope protein 2 (E2) from the serotype specific Venezuelan Equine Encephalitis Virus (VEEVcon) or a broad-spectrum AV-antigen termed EVCcon. The CPQ adjuvant enhanced the antigenicity of both proteins without eliciting detectable anti-His-tag antibodies. Antibodies elicited from mice immunized with antigens admixed with CPQ showed orders-of-magnitude higher levels of antigen-specific IgG compared to alternative control adjuvants. The ELISA results correlated with antiviral activity against VEEV strain TC83 and more weakly to Chikungunya virus 118/25. Thus, display of E.coli-produced His-tagged E2 protein segments on the surface of immunogenic liposomes elicits high levels of antigen-specific and AV neutralizing antibodies in mice with vaccination, while facilitating vaccine preparation and providing dose-sparing potential.

Preclinical evaluation of performance, safety and usability of VAX-ID®, a novel intradermal injection device

The recent SARS-Cov2 pandemic and mpox health emergency have led to renewed interest in intradermal vaccination due to its dose sparing potential. Indeed, intradermal vaccination is particularly of interest for use in mass vaccination campaigns, pandemic preparedness programs, and/or for vaccines that are expensive or in short supply. Moreover, the rich immune network in the skin makes it an attractive target not only for prophylactic vaccination, but also for therapeutic vaccination, like immunotherapy and (dendritic) cell-based therapies.The aim of the current paper was to provide an overview of preclinical data generated with VAX-ID®, a novel intradermal drug delivery device, to allow assessing it performance, safety and usability. The device can overcome challenges seen with the Mantoux technique whereby the needle needs to be inserted under a shallow angle. Various parameters of VAX-ID® were evaluated, including dead-space volume, dose accuracy, penetration depth & liquid deposit in piglets, as well as usability by healthcare professionals.The device has shown to have a low dead volume and a high dose accuracy. Importantly, the device performed successful injections at a predefined depth into the dermis with a high safety profile as confirmed by visual and histological evaluation in piglets. Moreover, the device was rated as easy to use by healthcare professionals.The combined preclinical performance and usability findings indicate that VAX-ID® can provide reliable, standardized and accurate drug delivery in the dermal layer of the skin with a high ease of use. The device offers a solution for injection of various prophylactic as well as therapeutic vaccines.

Sustained antigens delivery using composite microneedles for effective epicutaneous immunotherapy.

Allergen-specific immunotherapy (SIT) is a desirable way of therapy for various allergic diseases such as food allergy (FA). However, frequent visits for more than 3 years and potential adverse effects often hinder patient compliance. Recently, many researchers started focusing on microneedles (MNs) as a new method for SIT. In this study, we proposed an implantable MNs system produced by a two-step casting process, consisting of OVA (antigen)-loaded silk microneedles and a dissolvable, flexible polyvinyl alcohol (PVA) pedestal. Different from PVA, silk fibroin hydrogel has preferable vaccine release ability in vivo and in vitro. Once MNs are inserted into the skin, the PVA pedestal can dissolve in the interstitial fluid of the excised skin within 5 min and implant the OVA-loaded silk microneedle tips in dermal layer as a sustained antigen depot, thus inducing long-lasting immune response for at least 2 weeks. After receiving 3 doses of MN-based immunotherapy, the immune response in OVA-sensitized mice was successfully suppressed, with no apparent side effects. Compared to conventional subcutaneous immunotherapy (total dose of 150 [Formula: see text]g), MN immunotherapy ameliorated systemic anaphylaxis more effectively even at a lower dose (total dose of 30 [Formula: see text]g), demonstrating the antigen dose-sparing potential of the proposed MNs. Moreover, due to the prolonged release effect of silk-PVA composite MNs, the frequency of immunotherapy can be significantly reduced. To sum up, through prolonged skin exposure to antigen, this implantable designed MN may offer a new therapeutic strategy for FA treatment with significant improvements in efficacy and convenience. Schematic illustration of silk-PVA composite microneedles, consisting of OVA (antigen)-loaded silk microneedles and a dissolvable, flexible PVA pedestal. Once inserted into the skin, the PVA pedestal can dissolve in the interstitial fluid of the excised skin within 5 min. Subsequently, the OVA-loaded silk microneedle tips were implanted in the dermal layer as a sustained antigen depot and induced long-lasting immune response. This MNs-based immunotherapy can significantly modulate the Th1/Th2 imbalance of sensitized mice.

Safety and efficacy of the Novavax vaccine—a narrative review

Mass vaccination programs are a public health priority for managing the global coronavirus disease (COVID-19) pandemic. The NVX-CoV2373 vaccine is being developed by Novavax. It consists of a SARS-CoV-2 spike glycoprotein subunit (NVX-CoV2373), which has been shown to have structural stability with pH and temperature perturbations, and the saponin-based Matrix-M adjuvant, which is added to enhance the B- and T-cell-mediated immune response. Animal studies in mice, olive baboons, and cynomolgus macaques demonstrated the potential of this vaccine in protecting the respiratory tract against COVID-19. Subsequent phase 1 and 2 trials then confirmed its safety and the dose-sparing potential of Matrix-M. The results led to the use of a low dose (5 μg) of NVX-CoV2373 in phase 3 trials. In a phase 3 trial involving 14,039 participants, the vaccine efficacy rate was 89.7% (prevention of symptomatic infection). Local and systemic adverse events were mild and self-limiting; commonly reported symptoms included injection-site pain and tenderness, headache, myalgia, and fatigue. A subgroup study confirmed the safety and efficacy of co-administering the NVX-CoV2373 vaccine and the seasonal influenza vaccine. Overall, the vaccine has been found to be safe and effective, meeting the minimum vaccine efficacy rate of 50% to be considered for COVID-19 vaccine emergency use listing approval. Keywords: Clinical trials, COVID-19, COVID-19 vaccine, immunology

A liposome-displayed hemagglutinin vaccine platform protects mice and ferrets from heterologous influenza virus challenge

Recombinant influenza virus vaccines based on hemagglutinin (HA) hold the potential to accelerate production timelines and improve efficacy relative to traditional egg-based platforms. Here, we assess a vaccine adjuvant system comprised of immunogenic liposomes that spontaneously convert soluble antigens into a particle format, displayed on the bilayer surface. When trimeric H3 HA was presented on liposomes, antigen delivery to macrophages was improved in vitro, and strong functional antibody responses were induced following intramuscular immunization of mice. Protection was conferred against challenge with a heterologous strain of H3N2 virus, and naive mice were also protected following passive serum transfer. When admixed with the particle-forming liposomes, immunization reduced viral infection severity at vaccine doses as low as 2 ng HA, highlighting dose-sparing potential. In ferrets, immunization induced neutralizing antibodies that reduced the upper respiratory viral load upon challenge with a more modern, heterologous H3N2 viral strain. To demonstrate the flexibility and modular nature of the liposome system, 10 recombinant surface antigens representing distinct influenza virus strains were bound simultaneously to generate a highly multivalent protein particle that with 5 ng individual antigen dosing induced antibodies in mice that specifically recognized the constituent immunogens and conferred protection against heterologous H5N1 influenza virus challenge. Taken together, these results show that stable presentation of recombinant HA on immunogenic liposome surfaces in an arrayed fashion enhances functional immune responses and warrants further attention for the development of broadly protective influenza virus vaccines.

Effective and Safe Stimulation of Humoral and Cell-Mediated Immunity by Intradermal Immunization with a Cyclic Dinucleotide/Nanoparticle Combination Adjuvant.

Intradermal (ID) immunization is an attractive route of vaccination because it targets tissue rich in dendritic cells, has dose-sparing potential, and allows needle-free delivery. However, few adjuvants are effective, nonreactogenic, and compatible with needle-free delivery devices. In this study, we demonstrate that a combination adjuvant composed of cyclic-di-AMP (cdAMP) and the plant-derived nanoparticle adjuvant Nano-11 significantly enhanced the immune response to ID-injected vaccines in mice and pigs with minimal local reaction at the injection site. The cdAMP/Nano-11 combination adjuvant increased Ag uptake by lymph node-resident and migratory skin dendritic cell subpopulations, including Langerhans cells. ID immunization with cdAMP/Nano-11 expanded the population of germinal center B cells and follicular helper T cells in the draining lymph node and Ag-specific Th1 and Th17 cells in the spleen. It elicited an enhanced immune response with a significant increase of IgG1 and IgG2a responses in mice at a reduced dose compared with i.m. immunization. An increased IgG response was observed following needle-free ID immunization of pigs. Nano-11 and cdAMP demonstrated a strong synergistic interaction, as shown in the activation of mouse, human, and porcine APC, with increased expression of costimulatory molecules and secretion of TNF and IL-1β. The combination adjuvant induced robust activation of both NF-κB and IFN regulatory factor signaling pathways and the NLRP3 inflammasome. We conclude that the combination of Nano-11 and cdAMP is a promising adjuvant for ID delivery of vaccines that supports a balanced immune response.

Enhancing immunogenicity of antigens through sustained intradermal delivery using chitosan microneedles with a patch-dissolvable design

This study developed implantable chitosan microneedles (MNs) with a patch-dissolvable design for the sustained intradermal (ID) delivery of antigens and demonstrated their antigen dose-sparing potential. We found that rats immunized with chitosan MNs containing low-dose OVA had persistently high antibody levels for 18 weeks, which were significantly higher than those observed after an intramuscular injection of full-dose OVA, demonstrating at least 2.5-fold dose sparing. Our results indicate that chitosan MNs can not only serve as an efficient vaccine delivery system but also exert their promising adjuvant activity by forming an ID depot for prolonged antigen exposure and activating dendritic cells for promoting immune responses.

Modeling Combined Immunosuppressive and Anti-inflammatory Effects of Dexamethasone and Naproxen in Rats Predicts the Steroid-Sparing Potential of Naproxen.

Dexamethasone (DEX), a widely prescribed corticosteroid, has long been the cornerstone of the treatment of inflammation and immunologic dysfunctions in rheumatoid arthritis. Corticosteroids are frequently used in combination with other antirheumatic agents such as nonsteroidal anti-inflammatory drugs (NSAIDs) and disease-modifying antirheumatic drugs to mitigate disease symptoms and minimize unwanted effects. We explored the steroid dose-sparing potential of the NSAID naproxen (NPX) with in vitro and in vivo studies. The single and joint suppressive effects of DEX and NPX on the in vitro mitogen-induced proliferation of T lymphocytes in blood and their anti-inflammatory actions on paw edema were investigated in female and male Lewis rats with collagen-induced arthritis (CIA). As expected, DEX was far more potent than NPX in these systems. Mathematical models incorporating an interaction term ψ were applied to quantitatively assess the nature and intensity of pharmacodynamic interactions between DEX and NPX. Modest synergistic effects of the two drugs were found in suppressing the mitogenic response of T lymphocytes. A pharmacokinetic/pharmacodynamic/disease progression model integrating dual drug inhibition quantitatively described the pharmacokinetics, time-course of single and joint anti-inflammatory effects (paw edema), and sex differences in CIA rats, and indicated additive effects of DEX and NPX. Further model simulations demonstrated the promising steroid-sparing potential of NPX in CIA rats, with the beneficial effects of the combination therapy more likely in males than females.

High frequency ultrasound to assess skin thickness in healthy adults

BackgroundIntradermal immunization is gaining increased attention due to multiple factors: (1) intradermal (ID) vaccination has been shown to induce improved immunogenicity compared to intramuscular (IM) vaccination; (2) ID vaccination has been shown to have a dose-sparing potential over IM leading to a reduced vaccine cost and an increased availability of vaccines worldwide. However, the currently used Mantoux technique for ID injection is difficult to standardize and requires training.The aim of the study was (1) to assess the epidermal and dermal thickness at the proximal ventral and dorsal forearm (PVF & PDF) and deltoid in adults aged 18–65years (2) to determine the maximum penetration depth and needle characteristics for the development of a platform of medical devices suited for intradermal injection, VAX-ID™. Materials and methodsMean thickness of the PVF, PDF and deltoid were measured using high-frequency ultrasound of healthy adults aged 18–65years. Correlation with gender, age and BMI was assessed using Mann-Whitney U Test, Spearman correlation and Wilcoxon Signed Ranks Test, respectively. ResultsResults showed an overall mean skin thickness of 1.19mm (0.65–1.55mm) at the PVF, 1.44mm (0.78–1.84mm) at the PDF, and 2.12mm (1,16–3.19mm) at the deltoid. Thickness of PVF & PDF and deltoid were significantly different for men vs women (pmean<0.001, <0.001, <0.001, and pmin<0.001, 0.012, <0.001, respectively). A significant association was found for age at the deltoid region (p<0.001). Skin thickness for PVF, PDF & deltoid was significantly associated to BMI (p<0.001). ConclusionSignificant differences in skin thickness were seen for the PVF, PDF and deltoid region for gender, and BMI. Age only influenced the skin thickness at deltoid region. A needle length of 1.0mm is best option for intradermal injection at the dorsal forearm (NCT02363465).

Induction of Local Secretory IgA and Multifunctional CD4⁺ T-helper Cells Following Intranasal Immunization with a H5N1 Whole Inactivated Influenza Virus Vaccine in BALB/c Mice.

Avian influenza subunit vaccines have been shown to be poorly immunogenic, leading to the re-evaluation of the immunogenic and dose-sparing potential of whole virus vaccines. In this study, we investigated the immune responses after one or two doses of intramuscular or intranasal whole inactivated influenza H5N1 virus vaccine in BALB/c mice. Serum samples and nasal washings were collected weekly post-vaccination and analysed using enzyme-linked immunosorbent assay (ELISA). Sera were also analysed by the haemagglutination inhibition (HI) assay. Antibody-secreting cells were measured in lymphocytes from spleen and bone marrow via enzyme-linked immunospot (ELISPOT). Splenocytes were stimulated in vitro, and T-helper profiles were measured through multiplex bead assay in the supernatants, or intracellularly by multiparametric flow cytometry. Both vaccine routes induced high HI titres following the second immunization (intramuscular = 370, intranasal = 230). Moreover, the intramuscular group showed significantly higher levels of serum IgG (P < 0.01), IgG1 (P < 0.01) and IgG2a (P < 0.01) following the second vaccine dose, while the intranasal group exhibited significantly higher levels of serum IgA (P < 0.05) and local IgA (P < 0.01) in the nasal washings. Also, IgA antibody-secreting cells were found in significantly higher numbers in the intranasal group in both the spleen (P < 0.01) and the bone marrow (P < 0.01). Moreover, Th1 (TNF-α, IL-2, IFN-γ) and Th2 (IL-4, IL-5, IL-10) cytokines were expressed by both groups, yet only the intranasal group expressed the Th17 marker IL-17. As the intranasal vaccines induce local IgA and are easily administered, we suggest the intranasally administered whole virus vaccine as a promising candidate for a pandemic H5N1 vaccine.

EP-1629: Dose sparing potential of deep inspiration breath-hold technique for left breast radiotherapy organs-at-risk

EP-1629: Dose sparing potential of deep inspiration breath-hold technique for left breast radiotherapy organs-at-risk

Monophosphoryl lipid A coating of hydroxyethyl starch nanocapsules drastically increases uptake and maturation by dendritic cells while minimizing the adjuvant dosage

Enhancing delivery of antigens to dendritic cells (DCs) is essential for the induction of vigorous antigen-specific cellular immune responses. Aim of the present study was to evaluate the properties of hydroxyethyl starch nanocapsules (HES-NCs) functionalized with anti-CD40, anti-DEC205, interferon-γ (IFNγ) and/or monophosphoryl lipid A (MPLA) with respect to the overall uptake, the released cytokine profile, and the influence on phenotypic maturation of human monocyte-derived DCs using flow cytometry, confocal microscopy and enzyme-linked immunosorbent assays.NC uptake by DCs was significantly enhanced by functionalizing NCs with anti-CD40 or MPLA. With respect to the cytokine profile and the maturation status, coating with MPLA evoked a strong Th1-type cytokine response and significantly increased CD80 and CD83 expression on DCs, contrasting the moderate effects of MPLA in solution. Notably, an at least 20 fold higher amount of MPLA in solution was needed compared to the dosage of MPLA attached to HES-NCs in order to induce comparable effects, evidencing the intense dose-sparing potential of particle-bound MPLA.Reducing the amount of the vaccine adjuvant MPLA, while maintaining or even surpassing the effects on human DCs, reveals the potential of HES-NCs as a promising carrier system for the simultaneous delivery of antigen along with compounds promoting a Th1-prone cellular immune response.

Nebulized live-attenuated influenza vaccine provides protection in ferrets at a reduced dose

Live-attenuated influenza vaccine (LAIV) is delivered to vaccine recipients using a nasal spray syringe. LAIV delivered by this method is immunogenic at current doses; however, improvements in nasal delivery might allow for significant dose reduction. We investigated LAIV vaccination in ferrets using a high efficiency nebulizer designed for nasal delivery. LAIV nasal aerosol elicited high levels of serum neutralizing antibodies and protected ferrets from homologous virus challenge at conventional (107TCID50) and significantly reduced (103TCID50) doses. Aerosol LAIV also provided a significant level of subtype-specific cross-protection. These results demonstrate the dose-sparing potential of nebulizer-based nasal aerosol LAIV delivery.

New approaches for the control of influenza: the intradermal vaccination

The need of innovative influenza formulations to improve immunogenicity and effectiveness of conventional trivalent vaccines, subunit or split non-adjuvanted types, in groups of patients at risk of developing severe complications has facilitated the development of interesting lines of research in recent years. Moreover, the interest in the dose-sparing potential and the recent availability of innovative injection systems has led to a renewed attention in the intradermal (ID) administration of influenza vaccines. This new microinjection system (Soluvia ® , Beckton Dickinson, USA), currently the only intradermal device licensed for influenza vaccines, is a prefilled syringe with a single 30-gauge needle, 1.5 mm in length, that has a system specifically designed to limit the depth of penetration, reducing blood vessel and nerve injuries in patients. The sensation of injection is claimed to be almost imperceptible to the patient. The device is designed to protect the needle after injection, reducing risk of injury for health care workers. In recent years, numerous studies have been conducted with the aim of assessing the immunogenicity of ID vaccines, containing a dose of antigen equal to or lower than that contained in the non-adjuvanted intramuscular (IM) vaccine (15 μg/Hemagglutinin (HA) strain). The results of these studies demonstrate the ability of ID vaccines to elicit a good response even at lower doses of antigen, and to determine, at the same dose, a response even greater than that of the IM vaccines. This aspect is of crucial importance, especially in low-responders after IM. In this regard, a recent study of 3,707 subjects aged > 60 years, randomized to receive either a preparation ID or IM containing 15 μg of antigen demonstrated that

Intramuscular Matrix-M-adjuvanted virosomal H5N1 vaccine induces high frequencies of multifunctional Th1 CD4 + cells and strong antibody responses in mice

Ideally, a candidate pandemic influenza vaccine should elicit rapid and strong cell-mediated and humoral immune responses, which are long-lasting and exhibit broad cross-reactivity against drifted strains. The present study investigated the detailed humoral and cellular immune responses in mice vaccinated intranasally or intramuscularly with inactivated influenza H5N1 (NIBRG-14) virosomal vaccine alone or formulated with Matrix-M adjuvant. The intramuscular Matrix-M-adjuvanted vaccine induced a strong immediate and long-term humoral immune response with high cross-reactivity against drifted H5N1 viruses and showed a dose-sparing potential. Additionally, the vaccine induced a balanced Th1/Th2 cytokine profile and most importantly high frequencies of multifunctional Th1 CD4 + cells. Our results highlight that Matrix-M adjuvant is a promising parenteral adjuvant for formulating pandemic candidate vaccines.

Safety and Immunogenicity of an Inactivated Influenza A/H5N1 Vaccine Given with or without Aluminum Hydroxide to Healthy Adults: Results of a Phase I–II Randomized Clinical Trial

Dose-sparing strategies are being explored for vaccines against pandemic influenza. We evaluated the dose-sparing potential of aluminum hydroxide (AlOH) adjuvant. A total of 600 healthy subjects (age, 18-49 years) were randomized to receive 2 vaccinations 1 month apart with subvirion inactivated influenza A/H5N1 vaccine containing 7.5, 15, or 45 microg of hemagglutinin (HA), with or without 600 microg of aluminum hydroxide (AlOH), or 3.75 microg of HA, with or without 300 microg of AlOH. Serum specimens were obtained for antibody assays before and 1 month after each vaccination. All formulations were safe. Injection site discomfort was more frequent in groups given vaccines with AlOH. Dose-related increases in antibody responses were noted after both vaccinations (P< .001) geometric mean titers of hemagglutination inhibition antibody in vaccines with and without AlOH, respectively, were 5.4 and 5.4 for subjects who received 3.75 microg of HA, 7.7 and 5.3 for those who received 7.5 microg of HA, 8.1 and 8.5 for those who received 15 microg of HA, and 14.8 and 12 for those who received 45 microg of HA. A > or =4-fold increase in titer was observed in 2% and 2% of subjects who received 3.75 microg of HA with or without AlOH, respectively; in 14% and 0% who received 7 microg of HA; in 14% and 13% who received 15 microg of HA; and in 33% and 25% who received 45 microg of HA. Addition of AlOH enhanced responses only for subjects who received 7.5 microg of HA, but responses in subjects who received 7.5 microg of HA without AlOH were unexpectedly low. Overall, a meaningful beneficial effect of AlOH adjuvant was not observed. ClinicalTrials.gov identifier: NCT00296634 .