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1.
Proc Natl Acad Sci U S A ; 120(44): e2306465120, 2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37871214

RESUMO

Nucleic acid vaccines have shown promising results in the clinic against infectious diseases and cancers. To robustly improve the vaccine efficacy and safety, we developed an approach to increase the intracellular stability of nucleic acids by transiently inhibiting lysosomal function in targeted tissues using sucrose. To achieve efficient and localized delivery of sucrose in animals, we designed a biomimetic lipid nanoparticle (LNP) to target the delivery of sucrose into mouse muscle cells. Using this approach, viral antigen expression in mouse muscle after DNA vaccination was substantially increased and prolonged without inducing local or systemic inflammation or toxicity. The same change in antigen expression would be achieved if the vaccine dose could be increased by 3,000 folds, which is experimentally and clinically impractical due to material restrictions and severe toxicity that will be induced by such a high dose of nucleic acids. The increase in antigen expression augmented the infiltration and activation of antigen-presenting cells, significantly improved vaccine-elicited humoral and T cell responses, and fully protected mice against the viral challenge at a low dose of vaccine. Based on these observations, we conclude that transient inhibition of lysosome function in target tissue by sucrose LNPs is a safe and potent approach to substantially improve nucleic acid-based vaccines.


Assuntos
Nanopartículas , Ácidos Nucleicos , Vacinas de DNA , Vacinas , Animais , Camundongos , Vacinas Baseadas em Ácido Nucleico , Lisossomos , Sacarose
2.
Arch Biochem Biophys ; 756: 110022, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38697343

RESUMO

Cancer treatment has seen significant advancements with the introduction of Onco-immunotherapies (OIMTs). Although some of these therapies have received approval for use, others are either undergoing testing or are still in the early stages of development. Challenges persist in making immunotherapy widely applicable to cancer treatment. To maximize the benefits of immunotherapy and minimize potential side effects, it's essential to improve response rates across different immunotherapy methods. A promising development in this area is the use of extracellular vesicles (EVs) as novel delivery systems. These small vesicles can effectively deliver immunotherapies, enhancing their effectiveness and reducing harmful side effects. This article discusses the importance of integrating nanomedicines into OIMTs, highlighting the challenges with current anti-OIMT methods. It also explores key considerations for designing nanomedicines tailored for OIMTs, aiming to improve upon existing immunotherapy techniques. Additionally, the article looks into innovative approaches like biomimicry and the use of natural biomaterial-based nanocarriers (NCs). These advancements have the potential to transform the delivery of immunotherapy. Lastly, the article addresses the challenges of moving OIMTs from theory to clinical practice, providing insights into the future of using advanced nanotechnology in cancer treatment.


Assuntos
Vesículas Extracelulares , Imunoterapia , Neoplasias , Humanos , Neoplasias/terapia , Neoplasias/imunologia , Imunoterapia/métodos , Animais , Nanomedicina/métodos
3.
Microb Cell Fact ; 23(1): 61, 2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38402145

RESUMO

BACKGROUND: Helicobacter pylori (H. pylori) causes chronic gastric disease. An efficient oral vaccine would be mucosa-targeted and offer defense against colonization of invasive infection in the digestive system. Proteolytic enzymes and acidic environment in the gastrointestinal tract (GT) can, however, reduce the effectiveness of oral vaccinations. For the creation of an edible vaccine, L. lactis has been proposed as a means of delivering vaccine antigens. RESULTS: We developed a plSAM (pNZ8148-SAM) that expresses a multiepitope vaccine antigen SAM-WAE containing Urease, HpaA, HSP60, and NAP extracellularly (named LL-plSAM-WAE) to increase the efficacy of oral vaccinations. We then investigated the immunogenicity of LL-plSAM-WAE in Balb/c mice. Mice that received LL-plSAM-WAE or SAM-WAE with adjuvant showed increased levels of antibodies against H. pylori, including IgG and sIgA, and resulted in significant reductions in H. pylori colonization. Furthermore, we show that SAM-WAE and LL-plSAM-WAE improved the capacity to target the vaccine to M cells. CONCLUSIONS: These findings suggest that recombinant L. lactis could be a promising oral mucosa vaccination for preventing H. pylori infection.


Assuntos
Helicobacter pylori , Animais , Camundongos , Imunidade nas Mucosas , Fatores de Virulência , Vacinas Bacterianas , Urease , Vacinas Sintéticas , Camundongos Endogâmicos BALB C , Administração Oral
4.
J Appl Microbiol ; 135(7)2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38955370

RESUMO

AIMS: This study aims to evaluate the storage stability of the freeze-dried recombinant Lactococcus lactis NZ3900-fermented milk powder expressing K-ras (Kristen rat sarcoma viral oncogene homolog) mimotopes targeting colorectal cancer in vacuum packaging. METHODS AND RESULTS: The freeze-dried L. lactis-fermented milk powder stored in 4-ply retortable polypropylene (RCPP)-polyamide (PA)-aluminium (AL)-polyethylene terephthalate (PET) and aluminium polyethylene (ALPE) was evaluated throughout 49 days of accelerated storage (38°C and 90% relative humidity). The fermented milk powder stored in 4-ply packaging remained above 6 log10 CFU g-1 viability, displayed lower moisture content (6.1%), higher flowability (43° angle of repose), water solubility (62%), and survivability of L. lactis after simulated gastric and intestinal digestion (>82%) than ALPE packaging after 42 days of accelerated storage. K-ras mimotope expression was detected intracellularly and extracellularly in the freeze-dried L. lactis-fermented milk powder upon storage. CONCLUSIONS: This suggests that fermented milk powder is a suitable food carrier for this live oral vaccine.


Assuntos
Embalagem de Alimentos , Liofilização , Lactococcus lactis , Lactococcus lactis/metabolismo , Lactococcus lactis/genética , Embalagem de Alimentos/métodos , Animais , Vácuo , Pós , Produtos Fermentados do Leite/microbiologia , Fermentação , Leite/química , Genes ras/genética , Armazenamento de Alimentos
5.
J Nanobiotechnology ; 22(1): 480, 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39135073

RESUMO

Biomaterials are substances that can be injected, implanted, or applied to the surface of tissues in biomedical applications and have the ability to interact with biological systems to initiate therapeutic responses. Biomaterial-based vaccine delivery systems possess robust packaging capabilities, enabling sustained and localized drug release at the target site. Throughout the vaccine delivery process, they can contribute to protecting, stabilizing, and guiding the immunogen while also serving as adjuvants to enhance vaccine efficacy. In this article, we provide a comprehensive review of the contributions of biomaterials to the advancement of vaccine development. We begin by categorizing biomaterial types and properties, detailing their reprocessing strategies, and exploring several common delivery systems, such as polymeric nanoparticles, lipid nanoparticles, hydrogels, and microneedles. Additionally, we investigated how the physicochemical properties and delivery routes of biomaterials influence immune responses. Notably, we delve into the design considerations of biomaterials as vaccine adjuvants, showcasing their application in vaccine development for cancer, acquired immunodeficiency syndrome, influenza, corona virus disease 2019 (COVID-19), tuberculosis, malaria, and hepatitis B. Throughout this review, we highlight successful instances where biomaterials have enhanced vaccine efficacy and discuss the limitations and future directions of biomaterials in vaccine delivery and immunotherapy. This review aims to offer researchers a comprehensive understanding of the application of biomaterials in vaccine development and stimulate further progress in related fields.


Assuntos
Materiais Biocompatíveis , Sistemas de Liberação de Medicamentos , Vacinas , Materiais Biocompatíveis/química , Humanos , Animais , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/química , Hidrogéis/química , Desenvolvimento de Vacinas , COVID-19/prevenção & controle , Adjuvantes de Vacinas/química
6.
J Public Health (Oxf) ; 46(1): 151-157, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-37986235

RESUMO

BACKGROUND: Governments around the world used mobile vaccination units (MVUs) to increase COVID-19 vaccine uptake, but the causal effect of MVUs has not yet been evaluated. METHODS: In a randomized controlled trial (RCT) with 20 Swiss communities (10 treatment, 10 control) in August 2021, MVUs were sent to treatment communities for 4 hours on a single day. The experimental sample comprises 20 414 adults who were unvaccinated against COVID-19 at this point. The researchers designed the RCT and the government introduced the idea to test the effectiveness of MVUs and was responsible for administering the vaccines. RESULTS: The vaccination rate in the sample of the treatment group surpassed the rate in the control group by a factor of 3.4 (+9.0 percentage points) over 3 weeks. The increase was present and highly statistically significant for women, men and for all age groups. We found no evidence of cannibalization of vaccinations at other service locations. CONCLUSIONS: The offer of MVUs is highly effective in raising vaccination rates, even at a later point in the vaccination campaign. The absence of cannibalization effects suggests that MVUs reach more people overall, not just faster.


Assuntos
COVID-19 , Vacinas , Adulto , Masculino , Feminino , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Vacinação
7.
BMC Public Health ; 24(1): 185, 2024 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-38225582

RESUMO

BACKGROUND: This study analyses vaccine coverage and equity among children under five years of age in Uganda based on the 2016 Uganda Demographic and Health Survey (UDHS) dataset. Understanding equity in vaccine access and the determinants is crucial for the redress of emerging as well as persistent inequities. METHODS: Applied to the UDHS for 2000, 2006, 2011, and 2016, the Vaccine Economics Research for Sustainability and Equity (VERSE) Equity Toolkit provides a multivariate assessment of immunization coverage and equity by (1) ranking the sample population with a composite direct unfairness index, (2) generating quantitative measure of efficiency (coverage) and equity, and (3) decomposing inequity into its contributing factors. The direct unfairness ranking variable is the predicted vaccination coverage from a logistic model based upon fair and unfair sources of variation in vaccination coverage. Our fair source of variation is defined as the child's age - children too young to receive routine immunization are not expected to be vaccinated. Unfair sources of variation are the child's region of residence, and whether they live in an urban or rural area, the mother's education level, the household's socioeconomic status, the child's sex, and their insurance coverage status. For each unfair source of variation, we identify a "more privileged" situation. RESULTS: The coverage and equity of the Diphtheria-Pertussis-Tetanus vaccine, 3rd dose (DPT3) and the Measles-Containing Vaccine, 1st dose (MCV1) - two vaccines indicative of the health system's performance - improved significantly since 2000, from 49.7% to 76.8% and 67.8% to 82.7%, respectively, and there are fewer zero-dose children: from 8.4% to 2.2%. Improvements in retaining children in the program so that they complete the immunization schedule are more modest (from 38.1% to 40.8%). Progress in coverage was pro-poor, with concentration indices (wealth only) moving from 0.127 (DPT3) and 0.123 (MCV1) in 2000 to -0.042 and -0.029 in 2016. Gains in overall equity (composite) were more modest, albeit significant for most vaccines except for MCV1: concentration indices of 0.150 (DPT3) and 0.087 (MCV1) in 2000 and 0.054 and 0.055 in 2016. The influence of the region and settings (urban/rural) of residence significantly decreased since 2000. CONCLUSION: The past two decades have seen significant improvements in vaccine coverage and equity, thanks to the efforts to strengthen routine immunization and ongoing supplemental immunization activities such as the Family Health Days. While maintaining the regular provision of vaccines to all regions, efforts should be made to alleviate the impact of low maternal education and literacy on vaccination uptake.


Assuntos
Programas de Imunização , Vacinação , Criança , Humanos , Lactente , Pré-Escolar , Uganda , Cobertura Vacinal , Vacina contra Sarampo , Vacina contra Difteria, Tétano e Coqueluche
8.
J Immunoassay Immunochem ; : 1-17, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39169555

RESUMO

Conventional oral vaccine delivery in poultry is challenging due to vaccine degradation in the gastrointestinal (GI) environment and the need for cold-chain storage. Microencapsulation offers a solution by protecting vaccines from GI degradation and improving stability. Natural polymers like alginate and cashew gum have mucoadhesive properties, making them promising candidates for oral vaccine delivery. This study developed cashew-alginate microbeads and a powdered dose form for oral vaccine delivery in chickens. The microbeads were created using ionotropic gelation, while the powdered form was obtained via freeze-drying. These formulations were characterized for size, shape, and stability using scanning electron microscopy (SEM), light microscopy, X-ray diffraction (XRD), and Energy Dispersive X-ray (EDX). Peak adhesion time (PAT) was determined using chicken intestinal and esophageal tissues, and antigenicity was assessed with in-vitro hemagglutination (HA) and hemagglutination inhibition (HI) assays. The microbeads exhibited a spherical shape with a porous structure, suggesting enhanced antigen accommodation. Hemagglutination Inhibition tests indicated that the experimental vaccine remained effective without cold-chain storage for three months. These findings suggest that cashew-alginate microbeads are promising for oral vaccine delivery in poultry.

9.
Molecules ; 29(7)2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38611742

RESUMO

Tumor vaccines have been considered a promising therapeutic approach for treating cancer in recent years. With the development of sequencing technologies, tumor vaccines based on neoantigens or genomes specifically expressed in tumor cells, mainly in the form of peptides, nucleic acids, and dendritic cells, are beginning to receive widespread attention. Therefore, in this review, we have introduced different forms of neoantigen vaccines and discussed the development of these vaccines in treating cancer. Furthermore, neoantigen vaccines are influenced by factors such as antigen stability, weak immunogenicity, and biosafety in addition to sequencing technology. Hence, the biological nanomaterials, polymeric nanomaterials, inorganic nanomaterials, etc., used as vaccine carriers are principally summarized here, which may contribute to the design of neoantigen vaccines for improved stability and better efficacy.


Assuntos
Vacinas Anticâncer , Nanoestruturas , Neoplasias , Ácidos Nucleicos , Humanos , Vacinas Anticâncer/uso terapêutico , Medicina de Precisão , Nanoestruturas/uso terapêutico , Neoplasias/terapia
10.
Clin Microbiol Rev ; 35(1): e0012321, 2022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-34788128

RESUMO

Respiratory viral pathogens like influenza and coronaviruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have caused outbreaks leading to millions of deaths. Vaccinations are, to date, the best and most economical way to control such outbreaks and have been highly successful for several pathogens. Currently used vaccines for respiratory viral pathogens are primarily live attenuated or inactivated and can risk reversion to virulence or confer inadequate immunity. The recent trend of using potent biomolecules like DNA, RNA, and protein antigenic components to synthesize vaccines for diseases has shown promising results. Still, it remains challenging to translate due to their high susceptibility to degradation during storage and after delivery. Advances in bioengineering technology for vaccine design have made it possible to control the physicochemical properties of the vaccines for rapid synthesis, heightened antigen presentation, safer formulations, and more robust immunogenicity. Bioengineering techniques and materials have been used to synthesize several potent vaccines, approved or in trials, against coronavirus disease 2019 (COVID-19) and are being explored for influenza, SARS, and Middle East respiratory syndrome (MERS) vaccines as well. Here, we review bioengineering strategies such as the use of polymeric particles, liposomes, and virus-like particles in vaccine development against influenza and coronaviruses and the feasibility of adopting these technologies for clinical use.


Assuntos
COVID-19 , Desenvolvimento de Vacinas , Bioengenharia , Humanos , SARS-CoV-2 , Vacinação
11.
Annu Rev Microbiol ; 72: 273-292, 2018 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-30200856

RESUMO

Malaria vaccine development has rapidly advanced in the past decade. The very first phase 3 clinical trial of the RTS,S vaccine was completed with over 15,000 African infants and children, and pilot implementation studies are underway. Next-generation candidate vaccines using novel antigens, platforms, or approaches targeting different and/or multiple stages of the Plasmodium life cycle are being tested. Many candidates, in various stages of development, promise enhanced efficacy of long duration and broad protection against genetically diverse malaria strains, with a few studies under way in target populations in endemic areas. Malaria vaccines together with other interventions promise interruption and eventual elimination of malaria in endemic areas.


Assuntos
Descoberta de Drogas/tendências , Vacinas Antimaláricas/imunologia , Vacinas Antimaláricas/isolamento & purificação , Malária/prevenção & controle , Plasmodium/imunologia , Ensaios Clínicos Fase III como Assunto , Avaliação Pré-Clínica de Medicamentos , Humanos
12.
Pharm Res ; 40(2): 537-550, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36536098

RESUMO

PURPOSE: This study is the first vaccine candidate in vitro investigation with a focus on finding a correlation between the spray characteristics and the delivery efficiency of the local deposition in the nasal airways of infants under 24 months using various intranasal devices. METHODS: In vitro tests were developed to measure the spray characteristics of four intranasal delivery devices and how they regionally deliver a candidate vaccine formulation matrix in five nasal airway replicas (3 to 24 months). The correlation between the spray performance, geometric parameters, and delivery efficiency were assessed. RESULTS: All four devices performed consistently in terms of spray characteristics and were capable of delivering a high percentage of the candidate vaccine to the target areas, with a minimum delivery efficiency of 80%. Moreover, the delivery efficiency was affected by either the spray droplet size distribution or the distance between the nozzle tip and the internal nasal valve. Correlations between the spray performance and the in vitro local dose deposition were established. CONCLUSION: The infant nasal model tests can be complementary to device spray performance evaluation. In the absence of in vivo correlations, they can also facilitate the process of new product development by estimating delivery a priori.


Assuntos
Sistemas de Liberação de Medicamentos , Nebulizadores e Vaporizadores , Humanos , Aerossóis , Administração Intranasal , Nariz , Sprays Nasais
13.
Int J Mol Sci ; 24(13)2023 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-37446054

RESUMO

The development of efficient mucosal vaccines is strongly dependent on the use of appropriate vectors. Various biological systems or synthetic nanoparticles have been proposed to display and deliver antigens to mucosal surfaces. The Bacillus spore, a metabolically quiescent and extremely resistant cell, has also been proposed as a mucosal vaccine delivery system and shown able to conjugate the advantages of live and synthetic systems. Several antigens have been displayed on the spore by either recombinant or non-recombinant approaches, and antigen-specific immune responses have been observed in animals immunized by the oral or nasal route. Here we review the use of the bacterial spore as a mucosal vaccine vehicle focusing on the advantages and drawbacks of using the spore and of the recombinant vs. non-recombinant approach to display antigens on the spore surface. An overview of the immune responses induced by antigen-displaying spores so far tested in animals is presented and discussed.


Assuntos
Bacillus , Vacinas , Animais , Esporos Bacterianos/metabolismo , Bacillus subtilis/metabolismo , Vacinas/metabolismo , Sistemas de Liberação de Medicamentos , Bacillus/metabolismo , Antígenos/metabolismo , Proteínas de Bactérias/metabolismo
14.
Int J Mol Sci ; 24(10)2023 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-37240273

RESUMO

Colorectal cancer (CRC) is often caused by mutations in the KRAS oncogene, making KRAS neoantigens a promising vaccine candidate for immunotherapy. Secreting KRAS antigens using live Generally Recognized as Safe (GRAS) vaccine delivery hosts such as Lactococcus lactis is deemed to be an effective strategy in inducing specific desired responses. Recently, through the engineering of a novel signal peptide SPK1 from Pediococcus pentosaceus, an optimized secretion system was developed in the L. lactis NZ9000 host. In this study, the potential of the L. lactis NZ9000 as a vaccine delivery host for the production of two KRAS oncopeptides (mutant 68V-DT and wild-type KRAS) through the use of the signal peptide SPK1 and its mutated derivative (SPKM19) was investigated. The expression and secretion efficiency analyses of KRAS peptides from L. lactis were performed in vitro and in vivo in BALB/c mice. Contradictory to our previous study using the reporter staphylococcal nuclease (NUC), the yield of secreted KRAS antigens mediated by the target mutant signal peptide SPKM19 was significantly lower (by ~1.3-folds) compared to the wild-type SPK1. Consistently, a superior elevation of IgA response against KRAS aided by SPK1 rather than mutant SPKM19 was observed. Despite the lower specific IgA response for SPKM19, a positive IgA immune response from mice intestinal washes was successfully triggered following immunization. Size and secondary conformation of the mature proteins are suggested to be the contributing factors for these discrepancies. This study proves the potential of L. lactis NZ9000 as a host for oral vaccine delivery due to its ability to evoke the desired mucosal immune response in the gastrointestinal tract of mice.


Assuntos
Neoplasias Colorretais , Lactococcus lactis , Vacinas , Animais , Camundongos , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Antígenos/metabolismo , Imunidade nas Mucosas , Vacinas/metabolismo , Sinais Direcionadores de Proteínas , Imunoglobulina A/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/terapia
15.
Mol Pharm ; 19(9): 3358-3366, 2022 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-35984034

RESUMO

Cocaine is a highly addictive drug that has seen a steady uptrend causing severe health problems worldwide. Currently, there are no approved therapeutics for treating cocaine use disorder; hence, there is an urgent need to identify new medications. Immunopharmacotherapeutics is a promising approach utilizing endogenous antibodies generated through active vaccination, and if properly programmed, can blunt a drug's psychoactive and addictive effects. However, drug vaccine efficacy has largely been limited by the modest levels of antibodies induced. Herein, we explored an adjuvant system consisting of a polyphosphazene macromolecule, specifically poly[di(carboxylatoethylphenoxy)-phosphazene] (PCEP), a biocompatible synthetic polymer that was solicited for improved cocaine conjugate vaccine delivery performance. Our results demonstrated PCEP's superior assembling efficiency with a cocaine hapten as well as with the combined adjuvant CpG oligodeoxynucleotide (ODN). Importantly, this combination led to a higher titer response, balanced immunity, successful sequestering of cocaine in the blood, and a reduction in the drug in the brain. Moreover, a PCEP-cocaine conjugate vaccine was also found to function well via intranasal administration, where its efficacy was demonstrated through the antibody titer, affinity, mucosal IgA production, and a reduction in cocaine's locomotor activity. Overall, a comprehensive evaluation of PCEP integrated within a cocaine vaccine established an advance in the use of synthetic adjuvants in the drugs of abuse vaccine field.


Assuntos
Cocaína , Adjuvantes Imunológicos , Adjuvantes Farmacêuticos/farmacologia , Compostos Organofosforados , Polímeros , Desenvolvimento de Vacinas , Vacinas Conjugadas
16.
BMC Health Serv Res ; 22(1): 439, 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35379227

RESUMO

BACKGROUND: Vaccines are considered the path out of the COVID-19 pandemic. The government of Kenya is implementing a phased strategy to vaccinate the Kenyan population, initially targeting populations at high risk of severe disease and infection. We estimated the financial and economic unit costs of procuring and delivering the COVID-19 vaccine in Kenya across various vaccination strategies. METHODS: We used an activity-based costing approach to estimate the incremental costs of COVID-19 vaccine delivery, from a health systems perspective. Document reviews and key informant interviews(n = 12) were done to inform the activities, assumptions and the resources required. Unit prices were derived from document reviews or from market prices. Both financial and economic vaccine procurement costs per person vaccinated with 2-doses, and the vaccine delivery costs per person vaccinated with 2-doses were estimated and reported in 2021USD. RESULTS: The financial costs of vaccine procurement per person vaccinated with 2-doses ranged from $2.89-$13.09 in the 30% and 100% coverage levels respectively, however, the economic cost was $17.34 across all strategies. Financial vaccine delivery costs per person vaccinated with 2-doses, ranged from $4.28-$3.29 in the 30% and 100% coverage strategies: While the economic delivery costs were two to three times higher than the financial costs. The total procurement and delivery costs per person vaccinated with 2-doses ranged from $7.34-$16.47 for the financial costs and $29.7-$24.68 for the economic costs for the 30% and 100% coverage respectively. With the exception of procurement costs, the main cost driver of financial and economic delivery costs was supply chain costs (47-59%) and advocacy, communication and social mobilization (29-35%) respectively. CONCLUSION: This analysis presents cost estimates that can be used to inform local policy and may further inform parameters used in cost-effectiveness models. The results could potentially be adapted and adjusted to country-specific assumptions to enhance applicability in similar low-and middle-income settings.


Assuntos
Vacinas contra COVID-19 , COVID-19 , COVID-19/epidemiologia , COVID-19/prevenção & controle , Humanos , Programas de Imunização , Quênia/epidemiologia , Pandemias
17.
Proc Natl Acad Sci U S A ; 116(33): 16473-16478, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31358641

RESUMO

Sustained exposure of lymphoid tissues to vaccine antigens promotes humoral immunity, but traditional bolus immunizations lead to rapid antigen clearance. We describe a technology to tailor vaccine kinetics in a needle-free platform translatable to human immunization. Solid pyramidal microneedle (MN) arrays were fabricated with silk fibroin protein tips encapsulating a stabilized HIV envelope trimer immunogen and adjuvant, supported on a dissolving polymer base. Upon brief skin application, vaccine-loaded silk tips are implanted in the epidermis/upper dermis where they release vaccine over a time period determined by the crystallinity of the silk matrix. Following MN immunization in mice, Env trimer was released over 2 wk in the skin, correlating with increased germinal center (GC) B cell responses, a ∼1,300-fold increase in serum IgG titers and a 16-fold increase in bone marrow (BM) plasma cells compared with bolus immunization. Thus, implantable MNs provide a practical means to substantially enhance humoral immunity to subunit vaccines.


Assuntos
Preparações de Ação Retardada/farmacologia , Imunidade Humoral , Agulhas , Próteses e Implantes , Vacinação , Animais , Formação de Anticorpos/imunologia , Antígenos/imunologia , Bombyx , Centro Germinativo/imunologia , Linfonodos/imunologia , Camundongos Endogâmicos BALB C , Seda , Pele
18.
Molecules ; 27(2)2022 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-35056718

RESUMO

The advancements in the field of nanotechnology have provided a great platform for the development of effective antiviral vaccines. Liposome-mediated delivery of antigens has been shown to induce the antigen-specific stimulation of the humoral and cell-mediated immune responses. Here, we prepared dried, reconstituted vesicles (DRVs) from DPPC liposomes and used them as the vaccine carrier system for the Middle East respiratory syndrome coronavirus papain-like protease (DRVs-MERS-CoV PLpro). MERS-CoV PLpro emulsified in the Incomplete Freund's Adjuvant (IFA-MERS-CoV PLpro) was used as a control. Immunization of mice with DRVs-MERS-CoV PLpro did not induce any notable toxicity, as revealed by the levels of the serum alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) in the blood of immunized mice. Immunization with DRVs-MERS-CoV PLpro induced greater antigen-specific antibody titer and switching of IgG1 isotyping to IgG2a as compared to immunization with IFA-MERS-CoV PLpro. Moreover, splenocytes from mice immunized with DRVs-MERS-CoV PLpro exhibited greater proliferation in response to antigen stimulation. Moreover, splenocytes from DRVs-MERS-CoV PLpro-immunized mice secreted significantly higher IFN-γ as compared to splenocytes from IFA-MERS-CoV PLpro mice. In summary, DRVs-MERS-CoV PLpro may prove to be an effective prophylactic formulation to prevent MERS-CoV infection.


Assuntos
Proteases Semelhantes à Papaína de Coronavírus/imunologia , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Vacinas Virais/administração & dosagem , Vacinas Virais/imunologia , Animais , Proliferação de Células , Infecções por Coronavirus/prevenção & controle , Feminino , Imunidade Celular , Imunidade Humoral , Imunização/métodos , Imunoglobulina G/sangue , Interferon gama/metabolismo , Lipossomos/administração & dosagem , Lipossomos/química , Lipossomos/imunologia , Lipossomos/toxicidade , Linfócitos/metabolismo , Camundongos , Vacinas Virais/química , Vacinas Virais/toxicidade
19.
Molecules ; 27(20)2022 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-36296526

RESUMO

Cancer vaccines have been considered promising therapeutic strategies and are often constructed from whole cells, attenuated pathogens, carbohydrates, peptides, nucleic acids, etc. However, the use of whole organisms or pathogens can elicit unwanted immune responses arising from unforeseen reactions to the vaccine components. On the other hand, synthetic vaccines, which contain antigens that are conjugated, often with carrier proteins, can overcome these issues. Therefore, in this review we have highlighted the synthetic approaches and discussed several bioconjugation strategies for developing antigen-based cancer vaccines. In addition, the major synthetic biology approaches that were used to develop genetically modified cancer vaccines and their progress in clinical research are summarized here. Furthermore, to boost the immune responses of any vaccines, the addition of suitable adjuvants and a proper delivery system are essential. Hence, this review also mentions the synthesis of adjuvants and utilization of biomaterial scaffolds, which may facilitate the design of future cancer vaccines.


Assuntos
Vacinas Anticâncer , Neoplasias , Ácidos Nucleicos , Humanos , Biologia Sintética , Desenvolvimento de Vacinas , Vacinas Sintéticas , Neoplasias/prevenção & controle , Adjuvantes Imunológicos/farmacologia , Antígenos , Peptídeos/química , Carboidratos , Proteínas de Transporte , Materiais Biocompatíveis
20.
Molecules ; 27(21)2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36364250

RESUMO

The in vivo potency of polyphosphazene immunoadjuvants is inherently linked to the ability of these ionic macromolecules to assemble with antigenic proteins in aqueous solutions and form physiologically stable supramolecular complexes. Therefore, in-depth knowledge of interactions in this biologically relevant system is a prerequisite for a better understanding of mechanism of immunoadjuvant activity. Present study explores a self-assembly of polyphosphazene immunoadjuvant-PCPP and a model antigen-lysozyme in a physiologically relevant environment-saline solution and neutral pH. Three analytical techniques were employed to characterize reaction thermodynamics, water-solute structural organization, and supramolecular dimensions: isothermal titration calorimetry (ITC), water proton nuclear magnetic resonance (wNMR), and dynamic light scattering (DLS). The formation of lysozyme-PCPP complexes at near physiological conditions was detected by all methods and the avidity was modulated by a physical state and dimensions of the assemblies. Thermodynamic analysis revealed the dissociation constant in micromolar range and the dominance of enthalpy factor in interactions, which is in line with previously suggested model of protein charge anisotropy and small persistence length of the polymer favoring the formation of high affinity complexes. The paper reports advantageous use of wNMR method for studying protein-polymer interactions, especially for low protein-load complexes.


Assuntos
Prótons , Água , Água/química , Muramidase , Polieletrólitos , Difusão Dinâmica da Luz , Calorimetria/métodos , Polímeros/química , Termodinâmica , Espectroscopia de Ressonância Magnética , Adjuvantes Imunológicos
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