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1.
J Fluoresc ; 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38639858

RESUMO

Two fluorescent probes, Y1-2 were synthesized from 2-acetonaphthone, 4-acetylbiphenyl, and phenyl hydrazine by Vilsmeier-Haack reaction and Knoevenagel condensation. Their recognition efficacies for N2H4 were tested by UV-visible absorption spectroscopy and fluorescence emission spectroscopy. The recognition mechanism were studies by density-functional theory calculations, and the effect of pH on N2H4 recognition was also studied. The results showed that the probe Y1-2 has high selectivity and a low detection limit for N2H4, and the recognition of N2H4 can be accomplished at physiological pH. The probes have had obvious aggregation-induced luminescence effect, large Stokes shift, high sensitivity, and can be successfully applied to live cell imaging.

2.
Respir Res ; 24(1): 246, 2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37828565

RESUMO

BACKGROUND: Although COVID-19 vaccines and their booster regimens protect against symptomatic infections and severe outcomes, there is limited evidence about their protection against asymptomatic and symptomatic infections in real-world settings, particularly when considering that the majority of SARS-CoV-2 Omicron infections were asymptomatic. We aimed to assess the effectiveness of the booster dose of inactivated vaccines in mainland China, i.e., Sinopharm (BBIBP-CorV) and Sinovac (CoronaVac), against Omicron infection in an Omicron BA.5 seeded epidemic. METHODS: Based on an infection-naive but highly vaccinated population in Urumqi, China, the study cohort comprised all 37,628 adults who had a contact history with individuals having SARS-CoV-2 infections, i.e., close contacts, between August 1 and September 7, 2022. To actively detect SARS-CoV-2 infections, RT-PCR tests were performed by local authorities on a daily basis for all close contacts, and a testing-positive status was considered a laboratory-confirmed outcome. The cohort of close contacts was matched at a ratio of 1:5 with the fully vaccinated (i.e., 2 doses) and booster vaccinated groups (i.e., 3 doses) according to sex, age strata, calendar date, and contact settings. Multivariate conditional logistic regression models were adopted to estimate the marginal effectiveness of the booster dose against Omicron BA.5 infection after adjusting for confounding variables. Subgroup analyses were performed to assess vaccine effectiveness (VE) in different strata of sex, age, the time lag from the last vaccine dose to exposure, and the vaccination status of the source case. Kaplan-Meier curves were employed to visualize the follow-up process and testing outcomes among different subgroups of the matched cohort. FINDINGS: Before matching, 37,099 adult close contacts were eligible for cohort enrolment. After matching, the 2-dose and 3-dose groups included 3317 and 16,051 contacts, and the proportions with Omicron infections were 1.03% and 0.62% among contacts in the 2-dose and 3-dose groups, respectively. We estimated that the adjusted effectiveness of the inactivated booster vaccine versus 2 doses against Omicron infection was 35.5% (95% CI 2.0, 57.5). The booster dose provided a higher level of protection, with an effectiveness of 60.2% (95% CI 22.8, 79.5) for 15-180 days after vaccination, but this VE decreased to 35.0% (95% CI 2.8, 56.5) after 180 days. Evidence for the protection of the booster dose was detected among young adults aged 18-39 years, but was not detected for those aged 40 years or older. INTERPRETATION: The receipt of the inactivated vaccine booster dose was associated with a significantly lower Omicron infection risk, and our findings confirmed the vaccine effectiveness (VE) of booster doses against Omicron BA.5 variants. Given the rapid evolution of SARS-CoV-2, we highlight the importance of continuously monitoring the protective performance of vaccines against the genetic variants of SARS-CoV-2, regardless of existing vaccine coverage.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Adulto Jovem , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Estudos de Coortes , SARS-CoV-2
3.
J Math Biol ; 87(3): 41, 2023 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-37561222

RESUMO

Nosocomial infections (hospital-acquired) has been an important public health problem, which may make those patients with infections or involved visitors and hospital personnel at higher risk of worse clinical outcomes or infection, and then consume more healthcare resources. Taking into account the stochasticity of the death and discharge rate of patients staying in hospitals, in this paper, we propose a stochastic dynamical model describing the transmission of nosocomial pathogens among patients admitted for hospital stays. The stochastic terms of the model are incorporated to capture the randomness arising from death and discharge processes of patients. Firstly, a sufficient condition is established for the stochastic extinction of disease. It shows that introducing randomness in the model will result in lower potential of nosocomial outbreaks. Further, we establish a threshold criterion on the existence of stationary distribution and ergodicity for any positive solution of the model. Particularly, the spectral radius form of stochastic threshold value is calculated in the special case. Moreover, the numerical simulations are conducted to both validate the theoretical results and investigate the effect of prevention and control strategies on the prevalence of nosocomial infection. We show that enhancing hygiene, targeting colonized and infected patients, improving antibiotic treatment accuracy, shortening treatment periods are all crucial factors to contain nosocomial infections.


Assuntos
Infecção Hospitalar , Humanos , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Infecção Hospitalar/prevenção & controle , Bactérias , Surtos de Doenças/prevenção & controle , Saúde Pública
4.
Bull Math Biol ; 84(5): 55, 2022 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-35377056

RESUMO

The sudden outbreak of SARS-CoV-2 has caused the shortage of medical resources around the world, especially in developing countries and underdeveloped regions. With the continuous increase in the duration of this disease, the control of migration of humans between regions or countries has to be relaxed. Based on this, we propose a two-patches mathematical model to simulate the transmission of SARS-CoV-2 among two-patches, asymptomatic infected humans and symptomatic infected humans, where a half-saturated detection rate function is also introduced to describe the effect of medical resources. By applying the methods of linearization and constructing a suitable Lyapunov function, the local and global stability of the disease-free equilibrium of this model without migration is obtained. Further, the existence of forward/backward bifurcation is analyzed, which is caused by the limited medical resources. This means that the elimination or prevalence of the disease no longer depends on the basic reproduction number but is closely related to the initial state of asymptomatic and symptomatic infected humans and the supply of medical resources. Finally, the global dynamics of the full model are discussed, and some numerical simulations are carried to explain the main results and the effects of migration and supply of medical resources on the transmission of disease.


Assuntos
COVID-19 , SARS-CoV-2 , Número Básico de Reprodução , COVID-19/epidemiologia , Humanos , Conceitos Matemáticos , Modelos Biológicos
5.
Nanomedicine ; 42: 102541, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35181525

RESUMO

Virus-like particles (VLPs), a kind of superior subunit vaccine, are assembled from the viral structural proteins with similar capsids to viruses. However, the efficiency of cell uptake is not satisfactory. We prepared flower-like mesoporous silica nanoparticles (SiNPs) with large pore channels and interior cavities to solve the problem. The highly loaded VLPs-SiNPs composites not only enhanced the stability of VLPs, but also delivered antigen to cells and improved the cellular uptake efficiency. Compared with naked VLPs, mice intramuscularly immunized with the VLPs-SiNPs composite induced higher specific antibodies, greater lymphocyte activation and higher level of cytokine secretion. Moreover, the VLPs-SiNPs composite as vaccine also promoted mucosal immune response through intranasal immune pathway. Therefore, the VLPs-SiNPs enable to induce strong cellular, humoral, and slight mucosal immune response through different immunization routes. These results are potentially useful for vaccine formulations and may provide further reference for vaccine design and delivery systems.


Assuntos
Nanopartículas , Vacinas de Partículas Semelhantes a Vírus , Animais , Anticorpos Antivirais , Imunidade nas Mucosas , Imunização/métodos , Camundongos , Dióxido de Silício
6.
J Appl Math Comput ; 68(6): 4331-4359, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36311054

RESUMO

In this paper, a disease transmission model coupled virus infection in host with incubation delay and environmental effects is studied. For the virus infection model in host with immune, latent delay and environmental virus invading, the threshold criteria on the global stability of antibody-free and antibody response infection equilibria are established. For the disease transmission model with incubation delay and immune response in host, basic reproduction number R 0 is defined, and the local stability of equilibria are established, i.e., the disease-free equilibrium is locally asymptotically stable if R 0 < 1 , and the endemic equilibrium is locally asymptotically stable if R 0 > 1 . Furthermore, the uniform persistence of positive solutions is studied while there is not the direct transmission of disease by the infected individuals. Finally, the numerical examples are presented to verify the main results.

7.
Nanomedicine ; 33: 102358, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33484882

RESUMO

Virus-like particle (VLP) vaccines have become one of the dominant vaccine candidates for foot-and-mouth disease (FMD). To further enhance the immunogenicity of VLP vaccines, gold nanocages (AuNCs) were selected as an adjuvant for the vaccine. Our experiments demonstrated that AuNCs had little biotoxicity in vivo and in vitro and improved the uptake of VLP in BHK-21 and RAW264.7 cell lines. The VLP-AuNCs activated DCs mainly through toll-like receptor 4 (TLR4) and promoted the secretion of IL-6, IL-1ß, and TNF-α. The conjugation of VLP and AuNCs triggered a strong immune response against FMD virus (FMDV) in mice and guinea pigs. The VLP-AuNCs significantly enhanced the proliferation of CD8+ T cells (P < 0.05) and the secretion of cellular immune-related cytokines (IFN-γ, P < 0.05; IL-12p70, P < 0.01) compared with VLP. The present study demonstrated that AuNCs, as a great potential adjuvant for FMDV VLP vaccines, significantly enhance the immune response.


Assuntos
Adjuvantes Imunológicos/química , Portadores de Fármacos/química , Febre Aftosa/prevenção & controle , Ouro/química , Nanopartículas Metálicas/química , Vacinas de Partículas Semelhantes a Vírus/química , Vacinas Virais/química , Adjuvantes Imunológicos/farmacologia , Animais , Melhoramento Biomédico , Linfócitos T CD8-Positivos , Permeabilidade da Membrana Celular , Proliferação de Células , Citocinas/metabolismo , Composição de Medicamentos , Liberação Controlada de Fármacos , Feminino , Vírus da Febre Aftosa , Cobaias , Camundongos , Camundongos Endogâmicos BALB C , Testes de Neutralização , Células RAW 264.7 , Vacinas de Partículas Semelhantes a Vírus/farmacologia , Vacinas Virais/farmacologia
8.
Chaos Solitons Fractals ; 144: 110683, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33551582

RESUMO

In this paper, a reaction-diffusion SIR epidemic model is proposed. It takes into account the individuals mobility, the time periodicity of the infection rate and recovery rate, and the general nonlinear incidence function, which contains a number of classical incidence functions. In our model, due to the introduction of the general nonlinear incidence function, the boundedness of the infected individuals can not be obtained, so we study the existence and nonexistence of periodic traveling wave solutions of original system with the aid of auxiliary system. The basic reproduction number R 0 and the critical wave speed c * are given. We obtained the existence and uniqueness of periodic traveling waves for each wave speed c > c * using the Schauder's fixed points theorem when R 0 > 1 . The nonexistence of periodic traveling waves for two cases (i) R 0 > 1 and 0 < c < c * , (ii) R 0 ≤ 1 and c ≥ 0 are also obtained. These results generalize and improve the existing conclusions. Finally, the numerical experiments support the theoretical results. The differences of traveling wave solution between periodic system and general aperiodic coefficient system are analyzed by numerical simulations.

9.
Microb Pathog ; 143: 104130, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32165331

RESUMO

Foot-and-mouth disease virus (FMDV) is the etiological agent of a highly contagious disease that affects cloven-hoofed animals. Virus-like particles (VLPs) can induce a robust immune response and deliver DNA and small molecules. In this study, a VLP-harboring pcDNA3.1/P12A3C plasmid was generated, and the protective immune response was characterized. Guinea pigs were injected with VLPs, naked DNA vaccine, DNA-loaded VLPs, or phosphate-buffered saline twice subcutaneously at four-week intervals. Results demonstrated that the VLPs protected the naked DNA from DNase degeneration and delivered the DNA into the cells in vitro. The DNA-loaded VLPs and the VLPs alone induced a similar level of specific antibodies (P > 0.05) except at 49 dpv (P < 0.05). The difference in interferon-γ was consistent with that in specific antibodies. The levels of neutralizing antibodies induced by the DNA-loaded VLPs were significantly higher than those of other samples (P < 0.01). Similarly, the lymphocyte proliferation by using DNA-loaded VLPs was significantly higher than those using other formulas after booster immunization. Vaccination with DNA-loaded VLPs provided higher protection (100%) against viral challenge compared with vaccination with VLPs (75%) and DNA vaccine (25%). This study suggested that VLPs can be used as a delivery carrier for DNA vaccine. In turn, the DNA vaccine can enhance the immune response and prolong the serological duration of the VLP vaccine. This phenomenon contributes in providing complete protection against the FMDV challenge in guinea pigs and can be valuable in exploring novel nonreplicating vaccines and controlling FMD in endemic countries worldwide.


Assuntos
DNA Viral/administração & dosagem , Vírus da Febre Aftosa , Febre Aftosa/prevenção & controle , Vacinas de Partículas Semelhantes a Vírus/uso terapêutico , Vacinas Virais/uso terapêutico , Animais , DNA Viral/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Febre Aftosa/imunologia , Febre Aftosa/virologia , Vírus da Febre Aftosa/genética , Vírus da Febre Aftosa/imunologia , Cobaias , Testes de Neutralização , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas Virais/administração & dosagem
10.
Bull World Health Organ ; 98(12): 830-841D, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33293743

RESUMO

OBJECTIVE: To design models of the spread of coronavirus disease-2019 (COVID-19) in Wuhan and the effect of Fangcang shelter hospitals (rapidly-built temporary hospitals) on the control of the epidemic. METHODS: We used data on daily reported confirmed cases of COVID-19, recovered cases and deaths from the official website of the Wuhan Municipal Health Commission to build compartmental models for three phases of the COVID-19 epidemic. We incorporated the hospital-bed capacity of both designated and Fangcang shelter hospitals. We used the models to assess the success of the strategy adopted in Wuhan to control the COVID-19 epidemic. FINDINGS: Based on the 13 348 Fangcang shelter hospitals beds used in practice, our models show that if the Fangcang shelter hospitals had been opened on 6 February (a day after their actual opening), the total number of COVID-19 cases would have reached 7 413 798 (instead of 50 844) with 1 396 017 deaths (instead of 5003), and the epidemic would have lasted for 179 days (instead of 71). CONCLUSION: While the designated hospitals saved lives of patients with severe COVID-19, it was the increased hospital-bed capacity of the large number of Fangcang shelter hospitals that helped slow and eventually stop the COVID-19 epidemic in Wuhan. Given the current global pandemic of COVID-19, our study suggests that increasing hospital-bed capacity, especially through temporary hospitals such as Fangcang shelter hospitals, to isolate groups of people with mild symptoms within an affected region could help curb and eventually stop COVID-19 outbreaks in communities where effective household isolation is not possible.


Assuntos
COVID-19/epidemiologia , COVID-19/terapia , Número de Leitos em Hospital/estatística & dados numéricos , Unidades Móveis de Saúde/organização & administração , China/epidemiologia , Humanos , Cadeias de Markov , Modelos Estatísticos , Pandemias , SARS-CoV-2
11.
Mol Cell Probes ; 53: 101643, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32768439

RESUMO

Porcine vesicular disease caused by Senecavirus A (SVA) is a newly emerging disease in many countries. Based on clinical signs only, it is very challenging to distinguish SVA infection from other similar diseases, such as foot and mouth disease, swine vesicular disease, and vesicular stomatitis. Therefore, it is crucial to establish a detection assay for the clinical diagnosis of SVA infection. In this study, a pair of specific primers were designed based on the highly conserved L/VP4 gene sequence of SVA. The established SYBR green I-based quantitative reverse transcription polymerase chain reaction (qRT-PCR) method was used to detect SVA nucleic acids in clinical samples. The limit of detection SVA nucleic acids by qRT-PCR was 6.4 × 101 copies/µL, which was significantly more sensitive than that by gel electrophoresis of 6.4 × 103 copes/µL. This assay was specific and had no cross-reaction with other seven swine viruses. Using SYBR green I-based qRT-PCR, the SVA positive rates in experimental animal samples and field samples were 67.60% (96/142) and 80% (24/30) respectively. The results demonstrate that SYBR green I-based qRT-PCR is a rapid and specific method for the clinical diagnosis and epidemiological investigation of related vesicular diseases caused by SVA.


Assuntos
Benzotiazóis/química , Proteínas do Capsídeo/genética , Diaminas/química , Picornaviridae/isolamento & purificação , Quinolinas/química , Doença Vesicular Suína/diagnóstico , Animais , Limite de Detecção , Picornaviridae/genética , Infecções por Picornaviridae/diagnóstico , Infecções por Picornaviridae/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Suínos , Doenças dos Suínos/virologia , Doença Vesicular Suína/virologia
12.
Chaos Solitons Fractals ; 139: 110024, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32834590

RESUMO

In this paper, an age-structured epidemic model for coupling within-host and between-host dynamics in environmentally-driven infectious diseases is investigated. The model is described by a mixed system of ordinary and partial differential equations which is constituted by the within-host virus infectious fast time ordinary system and the between-host disease transmission slow time age-structured system. The isolated fast system has been investigated in previous literatures, and the main results are introduced. For the isolated slow system, the basic reproduction number R b0, the positivity and ultimate boundedness of solutions are obtained, the existence of equilibria, the local stability of equilibria, and the global stability of disease-free equilibrium are established. We see that when R b0 ≤ 1 the system only has the disease-free equilibrium which is globally asymptotically stable, and when R b0 > 1 the system has a unique endemic equilibrium which is local asymptotically stable. With regard to the coupled slow system, the basic reproduction number Rb , the positivity and boundedness of solutions and the existence of equilibria are firstly obtained. Particularly, the coupled slow system can exist two positive equilibria when Rb  < 1 and a unique endemic equilibrium when Rb  > 1. When Rb  < 1 the disease-free equilibrium is local asymptotically stable, and when Rb  > 1 and an additional condition is satisfied the unique endemic equilibrium is local asymptotically stable. When there exist two positive equilibria, under an additional condition the local asymptotic stability of a positive equilibrium and the instability of other positive equilibrium also are established. The numerical examples show that the additional condition may be removed. The research shows that the coupled slow age-structured system has more complex dynamical behavior than the corresponding isolated slow system.

13.
J Theor Biol ; 446: 212-228, 2018 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-29499250

RESUMO

In this paper, a parasitism-mutualism-predation model is proposed to investigate the dynamics of multi-interactions among cuckoos, crows and cats with stage-structure and maturation time delays on cuckoos and crows. The crows permit the cuckoos to parasitize their nestlings (eggs) on the crow chicks (eggs). In return, the cuckoo nestlings produce a malodorous cloacal secretion to protect the crow chicks from predation by the cats, which is apparently beneficial to both the crow and cuckoo population. The multi-interactions, i.e., parasitism and mutualism between the cuckoos (nestlings) and crows (chicks), predation between the cats and crow chicks are modeled both by Holling-type II and Beddington-DeAngelis-type functional responses. The existence of positive equilibria of three subsystems of the model are discussed. The criteria for the global stability of the trivial equilibrium are established by the Krein-Rutman theorem and other analysis methods. Moreover, the threshold dynamics for the coexistence and weak persistence of the model are obtained, and we show, both analytically and numerically, that the stabilities of the interior equilibria may change with the increasing maturation time delays. We find there exists an evident difference in the dynamical properties of the parasitism-mutualism-predation model based on whether or not we consider the effects of stage-structure and maturation time delays on cuckoos and crows. Inclusion of stage structure results in many varied dynamical complexities which are difficult to encompass without this inclusion.


Assuntos
Gatos/fisiologia , Corvos/fisiologia , Modelos Biológicos , Passeriformes/fisiologia , Comportamento Predatório/fisiologia , Simbiose , Animais
14.
Physica A ; 492: 1604-1624, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32288103

RESUMO

In this paper, we investigate the dynamical behavior for a stochastic SIS epidemic model with isolation which is as an important strategy for the elimination of infectious diseases. It is assumed that the stochastic effects manifest themselves mainly as fluctuation in the transmission coefficient, the death rate and the proportional coefficient of the isolation of infective. It is shown that the extinction and persistence in the mean of the model are determined by a threshold value R 0 S . That is, if R 0 S < 1 , then disease dies out with probability one, and if R 0 S > 1 , then the disease is stochastic persistent in the means with probability one. Furthermore, the existence of a unique stationary distribution is discussed, and the sufficient conditions are established by using the Lyapunov function method. Finally, some numerical examples are carried out to confirm the analytical results.

15.
Nanomedicine ; 13(3): 1061-1070, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27993721

RESUMO

The surface of foot-and-mouth disease virus (FMDV)-like particles (VLPs) contains a conserved arginine-glycine-aspartic acid (RGD) motif. Natural FMDV specifically attaches to overexpressed integrin receptors in several cancer cells. The FMDV VLPs produced in Escherichia coli were used for the first time as a delivery system of anti-tumor drug doxorubicin (DOX). The DOX-loaded VLPs exhibited a distinct release profile in different physiological conditions. The effects of FMDV-VLPs-DOX on cellular internalization and viability were evaluated in vitro by cell imaging, MTT assay and apoptosis, respectively. The anti-tumor efficacy in vivo was also determined in a nude mouse xenograft model based on tumor volume/weight and histological changes. The FMDV-VLPs-DOX complex significantly inhibited the proliferation of tumor and improved the pathological damage of DOX to non-targeting tissues. All results supported the potential of FMDV VLPs as a platform for specific targeted delivery of drugs or chemical reagents.


Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Doxorrubicina/administração & dosagem , Portadores de Fármacos/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Vírus da Febre Aftosa/metabolismo , Integrinas/metabolismo , Oligopeptídeos/metabolismo , Animais , Antibióticos Antineoplásicos/farmacologia , Antibióticos Antineoplásicos/uso terapêutico , Gatos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Portadores de Fármacos/química , Vírus da Febre Aftosa/química , Células HeLa , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Oligopeptídeos/química
16.
Nonlinear Dyn ; 77(4): 1223-1236, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-32214669

RESUMO

With the consideration of mechanism of prevention and control for the spread of viral diseases, in this paper, we propose two novel virus dynamics models where state feedback control strategies are introduced. The first model incorporates the density of infected cells (or free virus) as control threshold value; we analytically show the existence and orbit stability of positive periodic solution. Theoretical results imply that the density of infected cells (or free virus) can be controlled within an adequate level. The other model determines the control strategies by monitoring the density of uninfected cells when it reaches a risk threshold value. We analytically prove the existence and orbit stability of semi-trivial periodic solution, which show that the viral disease dies out. Numerical simulations are carried out to illustrate the main results.

17.
ACS Appl Bio Mater ; 7(2): 1064-1072, 2024 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-38286026

RESUMO

Virus-like particle (VLP) vaccine is considered to be the most promising candidate alternative to the traditional inactivated vaccine for foot-and-mouth disease (FMD). To elicit a desired immune response, hollow mesoporous silica nanoparticles (HMSNs) have been synthesized and utilized as a nanocarrier for FMD VLP vaccine delivery. The as-prepared HMSNs displayed a relatively small particle size (∼260 nm), large cavity (∼150 nm), and thin wall (∼55 nm). The inherent structural superiorities make them ideal nanocarriers for the FMD VLP vaccine, which exhibited good biocompatibility, great protein-loading capacity, high antibody-response level, and protective efficiency, even comparable to commercial adjuvant ISA 206. All the results suggested that HMSNs may be a valid nanocarrier in VLP-based vaccines.


Assuntos
Vírus da Febre Aftosa , Febre Aftosa , Nanopartículas , Vacinas , Animais , Dióxido de Silício/química , Febre Aftosa/prevenção & controle , Nanopartículas/química
18.
Vaccine ; 42(18): 3789-3801, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38714448

RESUMO

Inactivated vaccines lack the capability to serologically differentiate between infected and vaccinated animals, thereby impeding the effective eradication of pathogen. Conversely, vaccines based on virus-like particles (VLPs) emulate natural viruses in both size and antigenic structure, presenting a promising alternative to overcome these limitations. As the complexity of swine infectious diseases increases, the increase of vaccine types and doses may intensify the stress response. This exacerbation can lead to diminished productivity, failure of immunization, and elevated costs. Given the critical dynamics of co-infection and the clinically indistinguishable symptoms associated with foot-and-mouth disease virus (FMDV) and senecavirus A (SVA), there is a dire need for an efficacious intervention. To address these challenges, we developed a combined vaccine composed of three distinct VLPs, specifically designed to target SVA and FMDV serotypes O and A. Our research demonstrates that this trivalent VLP vaccine induces antigen-specific and robust serum antibody responses, comparable to those produced by the respective monovalent vaccines. Moreover, the immune sera from the combined VLP vaccine strongly neutralized FMDV type A and O, and SVA, with neutralization titers comparable to those of the individual vaccines, indicating a high level of immunogenic compatibility among the three VLP components. Importantly, the combined VLPs vaccines-immunized sera conferred efficient protection against single or mixed infections with FMDV type A and O, and SVA viruses in pigs. In contrast, individual vaccines could only protect pigs against homologous virus infections and not against heterologous challenges. This study presents a novel combined vaccines candidate against FMD and SVA, and provides new insights for the development of combination vaccines for other viral swine diseases.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Vírus da Febre Aftosa , Febre Aftosa , Picornaviridae , Doenças dos Suínos , Vacinas de Partículas Semelhantes a Vírus , Vacinas Virais , Animais , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Febre Aftosa/prevenção & controle , Febre Aftosa/imunologia , Vírus da Febre Aftosa/imunologia , Suínos , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/sangue , Vacinas Virais/imunologia , Vacinas Virais/administração & dosagem , Doenças dos Suínos/prevenção & controle , Doenças dos Suínos/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/sangue , Camundongos , Picornaviridae/imunologia , Infecções por Picornaviridae/prevenção & controle , Infecções por Picornaviridae/imunologia , Infecções por Picornaviridae/veterinária , Feminino , Vacinas Combinadas/imunologia , Vacinas Combinadas/administração & dosagem , Coinfecção/prevenção & controle , Coinfecção/imunologia
19.
Front Microbiol ; 15: 1386136, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38650887

RESUMO

Porcine epidemic diarrhea virus (PEDV) is considered the cause for porcine epidemic diarrhea (PED) outbreaks and hefty losses in pig farming. However, no effective commercial vaccines against PEDV mutant strains are available nowadays. Here, we constructed three native-like trimeric candidate nanovaccines, i.e., spike 1 trimer (S1-Trimer), collagenase equivalent domain trimer (COE-Trimer), and receptor-binding domain trimer (RBD-Trimer) for PEDV based on Trimer-Tag technology. And evaluated its physical properties and immune efficacy. The result showed that the candidate nanovaccines were safe for mice and pregnant sows, and no animal death or miscarriage occurred in our study. S1-Trimer showed stable physical properties, high cell uptake rate and receptor affinity. In the mouse, sow and piglet models, immunization of S1-Trimer induced high-level of humoral immunity containing PEDV-specific IgG and IgA. S1-Trimer-driven mucosal IgA responses and systemic IgG responses exhibited high titers of virus neutralizing antibodies (NAbs) in vitro. S1-Trimer induced Th1-biased cellular immune responses in mice. Moreover, the piglets from the S1-Trimer and inactivated vaccine groups displayed significantly fewer microscopic lesions in the intestinal tissue, with only one and two piglets showing mild diarrhea. The viral load in feces and intestines from the S1-Trimer and inactivated vaccine groups were significantly lower than those of the PBS group. For the first time, our data demonstrated the protective efficacy of Trimer-Tag-based nanovaccines used for PEDV. The S1-Trimer developed in this study was a competitive vaccine candidate, and Trimer-Tag may be an important platform for the rapid production of safe and effective subunit vaccines in the future.

20.
J Theor Biol ; 333: 78-90, 2013 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-23669505

RESUMO

Echinococcosis, which is one of the zoonotic diseases, can threaten human health and hinder the development of animal husbandry seriously. Especially in Xinjiang Uygur Autonomous Region of China, Echinococcosis is regarded as one of the most serious endemic diseases.The number of human Echinococcosis has increased dramatically in the last 10 years, partially due to poor understanding of the transmission dynamics of Echinococcosis and lack of effective control measures of the disease. In this paper, in order to explore effective control and prevention measures we propose a deterministic model to study the transmission dynamics of Echinococcosis in Xinjiang. The results show that the dynamics of the model is completely determined by the basic reproductive number R0. If R0<1, the disease-free equilibrium is globally asymptotically stable. When R0>1, the disease-free equilibrium is unstable, and the endemic equilibrium is globally asymptotically stable. Based on the data reported by Xinjiang Center for Disease Control and Prevention (Xinjiang CDC), the numerical simulation result matches Echinococcosis data well. The model provides an approximate estimate of the basic reproduction number R0=1.67. This indicates that Echinococcosis is endemic in Xinjiang with the current control measures. Finally, we perform some sensitivity analysis of several model parameters and give some useful comments on controlling the transmission of Echinococcosis.


Assuntos
Equinococose/epidemiologia , Equinococose/transmissão , Modelos Biológicos , Animais , China/epidemiologia , Feminino , Humanos , Masculino
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