RESUMO
BACKGROUND: Toxoplasma gondii is an intracellular opportunistic pathogenic protozoan that poses serious threats, particularly in immunocompromised individuals. In the absence of a robust prophylactic measure, the mitigation and management of toxoplasmosis present formidable challenges to public health. We recently found that GRA72 plays an important role in parasitophorous vacuole (PV) morphology, growth and virulence of T. gondii. However, whether gra72-deficient strain can be used as a vaccine remains unknown. METHODS: We first examined the attenuated virulence of gra72 gene knockout strain (PruΔgra72) and the parasite load in organs of the infected mice. Subsequently, we evaluated the immune-protective effects of the PruΔgra72 vaccination against challenge with various types of T. gondii tachyzoites and Pru cysts. Furthermore, levels of antibodies and cytokines induced by PruΔgra72 vaccination were examined. Statistical analysis was conducted by Student's t-test or Mantel-Cox log-rank test based on data obtained from three independent experiments with GraphPad Prism 8.0. RESULTS: We found that PruΔgra72 strain exhibited a significantly attenuated virulence even at the highest dose of 5 × 107 tachyzoites in Kunming mice model. The significant decrease of brain cyst burden and parasite load in the organs of the PruΔgra72-infected mice suggested its potentiality as a live-attenuated vaccine. Hence, we explored the protective immunity of PruΔgra72 vaccination against toxoplasmosis. Results showed that vaccination with 5 × 106 PruΔgra72 tachyzoites triggered a strong and sustained Th1-biased immune response, marked by significantly increased levels of anti-T. gondii IgG antibodies, and significantly higher levels of Th1 type cytokines (IL-2, IL-12 and IFN-γ) compared to that of Th2 type (IL-4 and IL-10). Vaccination with 5 × 106 PruΔgra72 tachyzoites in mice conferred long-term protection against T. gondii infection by less virulent tachyzoites (ToxoDB#9 PYS and Pru strains) and Pru cysts, provided partial protection against acute infection by high virulent Type I RH tachyzoites and significantly decreased brain cyst burden of chronically infected mice. CONCLUSIONS: The avirulent PruΔgra72 induced strong protective immunity against acute and chronic T. gondii infection and is a promising candidate for developing a safe and effective live-attenuated vaccine against T. gondii infection.
Assuntos
Anticorpos Antiprotozoários , Proteínas de Protozoários , Vacinas Protozoárias , Toxoplasma , Toxoplasmose Animal , Vacinas Atenuadas , Animais , Toxoplasma/imunologia , Toxoplasma/genética , Camundongos , Vacinas Protozoárias/imunologia , Vacinas Protozoárias/administração & dosagem , Vacinas Atenuadas/imunologia , Vacinas Atenuadas/administração & dosagem , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/genética , Anticorpos Antiprotozoários/sangue , Feminino , Toxoplasmose Animal/prevenção & controle , Toxoplasmose Animal/imunologia , Citocinas/metabolismo , Virulência , Carga Parasitária , Modelos Animais de Doenças , Doença Crônica , Toxoplasmose/prevenção & controle , Toxoplasmose/imunologia , Toxoplasmose/parasitologiaRESUMO
BACKGROUND: The highly expressed surface antigen 1 (SAG1)-related sequence (SRS) proteins of T. gondii tachyzoites, as a widespread zoonotic parasite, are critical for host cell invasion and represent promising vaccine targets. In this study, we employed a computer-aided multi-method approach for in silico design and evaluation of TgVax452, an epitope-based candidate vaccine against T. gondii tachyzoite-specific SRS proteins. METHODS: Using immunoinformatics web-based tools, structural modeling, and static/dynamic molecular simulations, we identified and screened B- and T-cell immunodominant epitopes and predicted TgVax452's antigenicity, stability, safety, adjuvanticity, and physico-chemical properties. RESULTS: The designed protein possessed 452 residues, a MW of 44.07 kDa, an alkaline pI (6.7), good stability (33.20), solubility (0.498), and antigenicity (0.9639) with no allergenicity. Comprehensive molecular dynamic (MD) simulation analyses confirmed the stable interaction (average potential energy: 3.3799 × 106 KJ/mol) between the TLR4 agonist residues (RS09 peptide) of the TgVax452 in interaction with human TLR4, potentially activating innate immune responses. Also, a dramatic increase was observed in specific antibodies (IgM and IgG), cytokines (IFN-γ), and lymphocyte responses, based on C-ImmSim outputs. Finally, we optimized TgVax452's codon adaptation and mRNA secondary structure for efficient expression in E. coli BL21 expression machinery. CONCLUSION: Our findings suggest that TgVax452 is a promising candidate vaccine against T. gondii tachyzoite-specific SRS proteins and requires further experimental studies for its potential use in preclinical trials.
Assuntos
Antígenos de Protozoários , Biologia Computacional , Epitopos de Linfócito T , Proteínas de Protozoários , Vacinas Protozoárias , Toxoplasma , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/genética , Proteínas de Protozoários/química , Toxoplasma/imunologia , Toxoplasma/genética , Toxoplasma/química , Vacinas Protozoárias/imunologia , Vacinas Protozoárias/genética , Antígenos de Protozoários/imunologia , Antígenos de Protozoários/genética , Antígenos de Protozoários/química , Animais , Camundongos , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/genética , Feminino , Anticorpos Antiprotozoários/imunologia , Camundongos Endogâmicos BALB C , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/química , Humanos , Simulação de Dinâmica Molecular , Epitopos Imunodominantes/imunologia , Epitopos Imunodominantes/genética , Epitopos Imunodominantes/química , Toxoplasmose/prevenção & controle , Toxoplasmose/imunologia , ImunoinformáticaRESUMO
Toxoplasmosis, a prevalent parasitic zoonotic disease, is influenced by various factors such as the climate, dietary habits, and hygiene practices. This study aimed to evaluate the knowledge, attitudes, and preventive behaviors regarding toxoplasmosis among females in Riyadh, Saudi Arabia. Utilizing a bilingual Google form, a cross-sectional online survey was distributed in both Arabic and English, and it was conducted between 11 January 2024 and 4 March 2024. Statistical analysis was conducted using SPSS Version 27, with a p-value ≤ 0.05 indicating significant qualitative data. The data were analyzed using descriptive statistics and the chi-square test. A total of 533 participants were included in the study. Participants aged 18-25 years old constituted the largest group (70.4%), with those aged 26-40 years old accounting for 14.4% and ages 41-60 years old comprising 15.2%. Among the participants, 76.4% were unmarried, and 21.4% were pregnant. Notably, 79.2% of participants reported being unaware of toxoplasmosis, with only 9.0% gaining awareness from doctors and a mere 3.6% from awareness campaigns. Any understanding of the disease's severity and causative factors was limited to 15.9%. Despite a generally positive attitude towards preventive measures, significant correlations were found between toxoplasmosis and age (p-value 0.093), as well as the consumption of medium-cooked meat (p-value 0.008). Other variables, such as social status, cat ownership, handwashing before meals, and washing fruits and vegetables did not show significant correlations. Diet and hygiene practices notably impact toxoplasmosis transmission. In Riyadh, 79% of participants did not own cats, and 67.7% avoided undercooked meat. However, 6.7% used unfiltered water, and 8.4% did not wash their hands after handling raw meat and vegetables. The study concludes that there is insufficient knowledge regarding toxoplasmosis among females in Riyadh. Despite low knowledge, there is a neutral to slightly positive attitude and a willingness to learn and adopt preventive measures when informed. With better education, attitudes towards toxoplasmosis could improve due to a desire to learn and act. While general hygiene practices were favorable, specific preventive behaviors for toxoplasmosis need enhancement to reduce infection risks.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Toxoplasmose , Humanos , Arábia Saudita/epidemiologia , Feminino , Estudos Transversais , Adulto , Toxoplasmose/prevenção & controle , Toxoplasmose/epidemiologia , Adulto Jovem , Pessoa de Meia-Idade , Adolescente , Inquéritos e Questionários , Comportamentos Relacionados com a SaúdeRESUMO
BACKGROUND: Toxoplasmosis is potentially avoidable, treatable, and curable by simple and direct preventive measures. Knowledge, attitudes, and practices (KAP) assessments concerning gestational toxoplasmosis were evaluated in a cohort of pregnant women from Armenia-Quindío (Colombia, South America). METHODS: This cross-sectional descriptive KAP-type study was performed with informed consent between October 2021 and March 2022. The intervention involved a ten-minute talk administered by prenatal clinic nurses to pregnant women. This took place in the public health clinic RedSalud and the private clinic Happy Maternity with a post-KAP survey after pregnancy. RESULTS: The findings of the initial KAP survey revealed that approximately 42.8 % of the 250 mothers surveyed had IgG anti-T. gondii antibodies present. A strong correlation was observed between a lower frequency of antibodies and a higher level of education. Following an educational intervention, 73 seronegative women demonstrated a significant improvement in their knowledge and behavior. Among the 111 mothers who received the intervention, 42 (37 %) were followed until delivery. Unfortunately, their level of compliance with prenatal serological follow-up was lower compared to previous historical records of cohort of mothers in the same health center during pre-pandemic periods. No seroconversion occurred, although the small number of cases makes the outcome inconclusive with respect to statistical significance. CONCLUSIONS: Education plays a crucial role in imparting valuable knowledge and fostering effective practices. It holds significant potential to prevent toxoplasmosis in pregnant seronegative mothers. Prenatal check-ups have proven to be a critical determinant in leveraging the benefits of education for seronegative mothers. Reporting and observed behaviors differed, identifying areas for improvement.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Toxoplasmose , Humanos , Feminino , Gravidez , Estudos Transversais , Adulto , Toxoplasmose/prevenção & controle , Adulto Jovem , Colômbia , Anticorpos Antiprotozoários/sangue , Toxoplasma/imunologia , Inquéritos e Questionários , Complicações Parasitárias na Gravidez/prevenção & controle , Gestantes/psicologia , Cuidado Pré-Natal , Imunoglobulina G/sangue , AdolescenteRESUMO
Toxoplasma gondii is an obligate intracellular parasite that can infect a variety of mammals including humans and causes toxoplasmosis. Unfortunately, a protective and safe vaccine against toxoplasmosis hasn't been developed yet. In this study, we developed a DNA vaccine encoding the SRS13 protein and immunized BALB/c mice thrice with pVAX1-SRS13 through the intramuscular route (IM) or intradermally using an electroporation device (ID + EP). The immunogenicity of pVAX1-SRS13 was analyzed by ELISA, Western blot, cytokine ELISA, and flow cytometry. The protective efficacy of the pVAX1-SRS13 was investigated by challenging mice orally with T. gondii PRU strain tissue cysts. The results revealed that pVAX1-SRS13 administered through IM or ID + EP routes induced high level of anti-SRS13 IgG antibody responses (P = 0.0037 and P < 0.0001). The IFN-γ level elicited by the pVAX1-SRS13 (ID + EP) was significantly higher compared to the control group (P = 0.00159). In mice administered with pVAX1-SRS13 (ID + EP), CD8+ cells secreting IFN-γ was significantly higher compared to pVAX1-SRS13 (IM) (P = 0.0035) and the control group (P = 0.0068). Mice vaccinated with the SRS13 DNA vaccine did not induce significant IL-4 level. Moreover, a significant reduction in the number of tissue cysts and the load of T. gondii DNA was detected in brains of mice administered with pVAX1-SRS13 through ID + EP and IM routes compared to controls. In conclusion, the SRS13 DNA vaccine was found to be highly immunogenic and confers strong protection against chronic toxoplasmosis.
Assuntos
Anticorpos Antiprotozoários , Eletroporação , Camundongos Endogâmicos BALB C , Proteínas de Protozoários , Vacinas Protozoárias , Toxoplasma , Vacinas de DNA , Vacinas de DNA/imunologia , Vacinas de DNA/administração & dosagem , Animais , Toxoplasma/imunologia , Toxoplasma/genética , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Eletroporação/métodos , Vacinas Protozoárias/imunologia , Vacinas Protozoárias/administração & dosagem , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/genética , Camundongos , Feminino , Toxoplasmose Animal/prevenção & controle , Toxoplasmose Animal/imunologia , Imunoglobulina G/sangue , Toxoplasmose/prevenção & controle , Toxoplasmose/imunologia , Antígenos de Protozoários/imunologia , Antígenos de Protozoários/genética , Interferon gama/imunologia , Linfócitos T CD8-Positivos/imunologiaRESUMO
Toxoplasma infection in humans is considered due to direct contact with infected cats. Toxoplasma infection (an endemic disease) has the potential to affect various organs and systems (brain, eyes, heart, lungs, liver, and lymph nodes). Bilinear incidence rate and constant population (birth rate is equal to death rate) are used in the literature to explain the dynamics of Toxoplasmosis disease transmission in humans and cats. The goal of this study is to consider the mathematical model of Toxoplasma disease with harmonic mean type incident rate and also consider that the population of humans and cats is not equal (birth rate and the death rate are not equal). In examining Toxoplasma transmission dynamics in humans and cats, harmonic mean incidence rates are better than bilinear incidence rates. The disease dynamics are first schematically illustrated, and then the law of mass action is applied to obtain nonlinear ordinary differential equations (ODEs). Analysis of the boundedness, positivity, and equilibrium points of the system has been analyzed. The reproduction number is calculated using the next-generation matrix technique. The stability of disease-free and endemic equilibrium are analyzed. Sensitivity analysis is also done for reproduction number. Numerical simulation shows that the infection is spread in the population when the contact rate ß h and ß c increases while the infection is reduced when the recovery rate δ h increases. This study investigates the impact of various optimal control strategies, such as vaccinations for the control of disease and the awareness of disease awareness, on the management of disease.
Assuntos
Toxoplasmose , Animais , Humanos , Toxoplasmose/transmissão , Toxoplasmose/epidemiologia , Toxoplasmose/prevenção & controle , Gatos , Incidência , Modelos Teóricos , Toxoplasma/patogenicidade , Toxoplasma/fisiologia , Simulação por ComputadorRESUMO
BACKGROUND: Toxoplasmosis is a parasitic infection caused by Toxoplasma gondii and is responsible for gestational and congenital infections worldwide. The current standard therapy is based on the administration of Spiramycin to prevent trans-placental transmission. Other therapies are being studied to reduce the rates of foetal transmission and symptomatic congenital infection. OBJECTIVES: We report our long-standing experience in maternal toxoplasmosis infection treatment using a combination of Spiramycin-Cotrimoxazole, assessing its effectiveness in preventing vertical transmission compared to the expected incidence of congenital infection. METHODS: We retrospectively collected cases of pregnant women referred to our centre for suspected toxoplasmosis infection according to Lebech criteria, treated with Spiramycin-Cotrimoxazole. RESULTS: Of 1364 women referred to our centre, postnatal follow-up of primary toxoplasmosis was available in 562 cases (73.9%). The overall vertical transmission rate was 3.4% in women treated immediately with Spiramycin-Cotrimoxazole after the diagnosis of infection. In comparison, it was 7.7% in women undergoing the same therapy but late or with poor compliance. The foetal transmission rate was 71.4% in untreated cases. All the infected newborns of mother treated adequately with Spiramycin-Cotrimoxazole were asymptomatic afterbirth, while 6/21 infected infants of the inadequate Spiramycin-Cotrimoxazole therapy group had postnatal sequelae (28.5%). The incidence of transmission after appropriate Spiramycin-Cotrimoxazole therapy was significantly lower than the expected rate reported in literature. CONCLUSIONS: A combination of Spiramycin and Cotrimoxazole is safe and effective in preventing foetal congenital toxoplasmosis and reducing sequelae in case of in-utero infection. The timing and adherence to the therapy are crucial to lowering the risk of congenital infection and neonatal morbidity.
Assuntos
Transmissão Vertical de Doenças Infecciosas , Complicações Parasitárias na Gravidez , Espiramicina , Centros de Atenção Terciária , Toxoplasmose Congênita , Combinação Trimetoprima e Sulfametoxazol , Humanos , Espiramicina/uso terapêutico , Feminino , Gravidez , Toxoplasmose Congênita/prevenção & controle , Toxoplasmose Congênita/tratamento farmacológico , Toxoplasmose Congênita/epidemiologia , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Estudos Retrospectivos , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Recém-Nascido , Complicações Parasitárias na Gravidez/prevenção & controle , Complicações Parasitárias na Gravidez/tratamento farmacológico , Complicações Parasitárias na Gravidez/epidemiologia , Adulto , Quimioterapia Combinada , Antibacterianos/uso terapêutico , Toxoplasmose/prevenção & controle , Toxoplasmose/transmissão , Toxoplasmose/tratamento farmacológico , Toxoplasmose/epidemiologia , Antiprotozoários/uso terapêuticoRESUMO
Toxoplasma gondii is a pervasive protozoan parasite that is responsible for significant zoonoses. A wide array of vaccines using different effector molecules of T. gondii have been studied worldwide to control toxoplasmosis. None of the existing vaccines are sufficiently effective to confer protective immunity. Among the different Toxoplasma-derived effector molecules, T. gondii dense granule protein 15 from the type II strain (GRA15 (II)) was recently characterized as an immunomodulatory molecule that induced host immunity via NF-κB. Therefore, we assessed the immunostimulatory and protective efficacy of recombinant GRA15 (II) (rGRA15) against T. gondii infection in a C57BL/6 mouse model. We observed that rGRA15 treatment increased the production of IL-12p40 from mouse peritoneal macrophages in vitro. Immunization of mice with rGRA15 induced the production of anti-TgGRA15-specific IgG, IgG1 and IgG2c antibodies. The rGRA15-sensitized spleen cells from mice inoculated with the same antigen strongly promoted spleen cell proliferation and IFN-γ production. Immunization with rGRA15 significantly enhanced the survival rate of mice and dramatically decreased parasite burden in mice challenged with the Pru (type II) strain. These results suggested that rGRA15 triggered humoral and cellular immune responses to control infection. However, all of the immunized mice died when challenged with the GRA15-deficient Pru strain or the RH (type I) strain. These results suggest that GRA15 (II)-dependent immunity plays a crucial role in protection against challenge infection with the type II strain of T. gondii. This study is the first report to show GRA15 (II) as a recombinant vaccine antigen against Toxoplasma infection.
Assuntos
Vacinas Protozoárias , Toxoplasma , Toxoplasmose Animal , Toxoplasmose , Vacinas de DNA , Vacinas , Animais , Camundongos , Proteínas de Protozoários , Camundongos Endogâmicos C57BL , Toxoplasmose/prevenção & controle , Proteínas Recombinantes/metabolismo , Anticorpos Antiprotozoários , Toxoplasmose Animal/prevenção & controle , Camundongos Endogâmicos BALB CRESUMO
Toxoplasmosis is one of the most dangerous zoonotic diseases, causing serious economic losses worldwide due to abortion and reproductive problems. Vaccination is the best way to prevent disease; thus, it is imperative to develop a candidate vaccine for toxoplasmosis. BAG1 and ROP8 have the potential to become vaccine candidates. In this study, rTgBAG1, rTgROP8, and rTgBAG1-rTgROP8 were used to evaluate the immune effect of vaccines in each group by detecting the humoral and cellular immune response levels of BABL/c mice after immunization and the ability to resist acute and chronic infection with Toxoplasma gondii (T. gondii). We divided the mice into vaccine groups with different proteins, and the mice were immunized on days 0, 14, and 28. The protective effects of different proteins against T. gondii were analysed by measuring the cytokines, serum antibodies, splenocyte proliferation assay results, survival time, and number and diameter of brain cysts of mice after infection. The vaccine groups exhibited substantially higher IgG, IgG1, and IgG2a levels and effectively stimulated lymphocyte proliferation. The levels of IFN-γ and IL-2 in the vaccine group were significantly increased. The survival time of the mice in each vaccine group was prolonged and the diameter of the cysts in the vaccine group was smaller; rTgBAG1-rTgROP8 had a better protection. Our study showed that the rTgBAG1, rTgROP8, and rTgBAG1-rTgROP8 recombinant protein vaccines are partial but effective approaches against acute or chronic T. gondii infection. They are potential candidates for a toxoplasmosis vaccine.
Assuntos
Vacinas Protozoárias , Toxoplasmose , Animais , Camundongos , Anticorpos Antiprotozoários , Antígenos de Protozoários/genética , Imunidade Celular , Imunização , Imunoglobulina G , Camundongos Endogâmicos BALB C , Proteínas de Protozoários , Vacinas Protozoárias/imunologia , Proteínas Recombinantes/genética , Toxoplasma , Toxoplasmose/prevenção & controle , VacinaçãoRESUMO
Toxoplasma gondii (T. gondii) is one of the most common pathogenic protozoa in the world, and causes toxoplasmosis, which in varying degrees causes significant economic losses and poses a serious public health challenge globally. To date, the development of an effective vaccine for human toxoplasmosis remains a challenge. Given that T.gondii calcium-dependent protein kinase 3 (CDPK3), dense granule protein 35 (GRA35) and rhoptry organelle protein 46 (ROP46) play key roles during Toxoplasma gondii invasion of host cells, we developed a protein vaccine cocktail including these proteins and validated its protective efficacy. The specific protective effects of vaccine on mice were analyzed by measuring serum antibodies, cytokines, splenocyte proliferation, the percentage of CD4+ and CD8+ T-lymphocytes, survival rate, and parasite cyst burden. The results showed that mice vaccinated with a three-protein cocktail produced the highest levels of immune protein antibodies to IgG, and high levels of IFN-γ, IL-2, IL-4, and IL-10 compared to other mice vaccinated with two proteins. In addition, CD4+ and CD8+ T cell percentages were significantly elevated. Compared to the control groups, mice vaccinated with the three-protein cocktail survived significantly longer after acute infection with T. gondii and had significantly fewer cysts after chronic infection. These results demonstrated that a cocktail vaccine of TgCDPK3, TgGRA35, and TgROP46 can effectively induce cellular and humoral immune responses with good protective effects in mice, indicating its potential as vaccine candidates for toxoplasmosis.
Assuntos
Proteínas Quinases , Vacinas Protozoárias , Toxoplasma , Toxoplasmose Animal , Toxoplasmose , Vacinas de DNA , Animais , Camundongos , Humanos , Camundongos Endogâmicos BALB C , Toxoplasmose/prevenção & controle , Proteínas de Protozoários/genética , Organelas , Anticorpos Antiprotozoários , Toxoplasmose Animal/prevenção & controleRESUMO
A few reports have been published and documented low level of awareness on toxoplasmosis among Saudi women. Herein, a cross sectional community based study was undertaken to evaluate basic knowledge on toxoplasmosis among residents in the Eastern province (Sharqiyah). Thisstudy was conducted between December 2022 and January 2023 on 334 females from different ages and educational backgrounds. Analysis of their responses revealed that only (24.9%) had heard about the disease. However, (69.8%) properly identified cats as the source of Toxoplasma gondii (T. gondii), but a smaller percentage (47.7%) knew that they might become infected through handling cat feces, and a few (26.3%) believed that bad hand hygiene can result in T. gondii infection. A few males (n = 26) have also participated, for the first time in Saudi Arabia, and displayed also low level of knowledge on toxoplasmosis. We do recommend establishing educational programs for females, in various Saudi provinces, to raise awareness on toxoplasmosis.
Assuntos
Toxoplasma , Toxoplasmose , Masculino , Feminino , Humanos , Arábia Saudita/epidemiologia , Estudos Transversais , Estudos Soroepidemiológicos , Toxoplasmose/epidemiologia , Toxoplasmose/prevenção & controle , Fatores de RiscoRESUMO
IMPORTANCE: Toxoplasma gondii, an obligate intracellular eukaryotic parasite, can infect about one-third of the world's population. One vaccine, Toxovax, has been developed and licensed commercially; however, it is only used in the sheep industry to reduce the losses caused by congenital toxoplasmosis. Various other vaccine approaches have been explored, including excretory secretion antigen vaccines, subunit vaccines, epitope vaccines, and DNA vaccines. However, current research has not yet developed a safe and effective vaccine for T. gondii. Here, we generated an mRNA vaccine candidate against T. gondii. We investigated the efficacy of vaccination with a novel identified candidate, TGGT1_278620, in a mouse infection model. We screened T. gondii-derived protective antigens at the genome-wide level, combined them with mRNA-lipid nanoparticle vaccine technology against T. gondii, and investigated immune-related factors and mechanisms. Our findings might contribute to developing vaccines for immunizing humans and animals against T. gondii.
Assuntos
Toxoplasma , Toxoplasmose , Vacinas de DNA , Humanos , Camundongos , Animais , Ovinos , Vacinas de mRNA , Camundongos Endogâmicos BALB C , Proteínas de Protozoários/genética , Imunidade Celular , Toxoplasmose/prevenção & controle , Toxoplasma/genética , Vacinas de DNA/genética , Antígenos de ProtozoáriosRESUMO
OBJECTIVE: To analyze the RNA binding protein of Toxoplasma gondii (TgDDX39) using bioinformatics technology, and to evaluate the immunogenicity of TgDDX39, so as to provide insights into development of toxoplasmosis vaccines. METHODS: The amino acid sequences of TgDDX39 were retrieved from the ToxoDB database, and the physicochemical properties, transmembrane structure domain, signal peptide sites, post-translational modification sites, coils, secondary and tertiary structures, hydrophobicity, and antigenic epitopes of the TgDDX39 protein were predicted using online bioinformatics tools, incluiding ProtParam, TMHMM 2.0, SignalP 5.0, NetPhos 3.1, COILS, SOPMA, Phyre2, ProtScale, ABCpred, SYFPEITHI and DNA-STAR. RESULTS: TgDDX39 protein was predicted to be an unstable hydrophilic protein with the molecular formula of C2173H3458N598O661S18, which contained 434 amino acids and had an estimated molecular weight of 49.1 kDa and a theoretical isoelectric point of 5.55. The protein was predicted to have an extremely low possibility of signal peptides, without transmembrane regions, and contain 27 phosphorylation sites. The ß turn and random coils accounted for 39.63% of the secondary structure of the TgDDX39 protein, and a coiled helix tended to produce in one site. In addition, the TgDDX39 protein contained multiple B and T cell antigenic epitopes. CONCLUSIONS: Bioinformatics analyses predict that TgDDX39 protein has high immunogenicity and contains multiple antigenic epitopes. TgDDX39 protein is a potential candidate antigen for vaccine development.
Assuntos
Toxoplasma , Toxoplasmose , Vacinas , Humanos , Toxoplasma/genética , Toxoplasma/metabolismo , Toxoplasmose/prevenção & controle , Epitopos de Linfócito T , Biologia Computacional , Proteínas de Protozoários/químicaRESUMO
Exosomes were isolated from T. gondii infected human hepatoblastoma cells using the exosome isolation kit and characterized by electron microscopy and Western blotting. Exosomes adsorbed to alum adjuvant were evaluated as a potential immunizing agent against murine chronic toxoplasmosis compared to excretory secretory antigens (ESA)-alum. Mice were immunized at days 1, 15 and 29. The levels of IgG, IFN-γ, IL-4 and IL-10, CD4+ and CD8+ T cells were determined using sandwich enzyme-linked immunosorbent assay (sandwich ELISA) at days 14, 28 and 56 of the experiment. Then mice were infected orally with 10 cysts of T. gondii. The protective efficacy of the antigens were evaluated by counting the brain cysts and measuring the aforementioned humoral and cellular parameters 60 days post infection. The results showed that alum increased the protective efficacy of the exosomes. Immunization with exosome-alum induced both humoral and mixed Th1/Th2 cellular immune responses. Exosome-alum gave higher levels of the humoral and cellular parameters, compared to ESA-alum. After challenge infection, exosome-alum significantly reduced the brain cyst burden by 75 % while ESA-alum gave 42 % reduction and evoked higher humoral and cellular immune responses. Therefore, the possibility of using T. gondii infected cells-derived exosome-alum as a vaccine is a new perspective in toxoplasmosis.
Assuntos
Exossomos , Vacinas Protozoárias , Toxoplasma , Toxoplasmose Animal , Toxoplasmose , Animais , Camundongos , Humanos , Linfócitos T CD8-Positivos , Toxoplasmose/prevenção & controle , Anticorpos Antiprotozoários , Proteínas de Protozoários , Antígenos de ProtozoáriosRESUMO
Toxoplasma gondii is a zoonotic parasite that is very common in livestock. Meat products from livestock infected with T. gondii are one of the important transmission routes of toxoplasmosis. Rapid and reliable diagnosis is a prerequisite for the prevention and control of toxoplasmosis. Neospora caninum and T. gondii are similar in morphology and life history, and there are a large number of cross antigens between them, making clinical diagnosis of toxoplasmosis more difficult. In this study, immunoprecipitation-mass spectrometry (IP-MS) was used to screen for T. gondii-specific antigens, and the specific antigen was cloned and expressed in Escherichia coli. The specific antigen was then used to establish an indirect ELISA diagnostic method. A total of 241 specific antigens of T. gondii and 662 cross antigens between T. gondii and N. caninum were screened by IP-MS. Through bioinformatics analysis and homology comparison, seven proteins were selected for gene cloning and prokaryotic expression, and the most suitable antigen, TgGRA54, was selected to establish an indirect ELISA for T. gondii. Compared with the indirect immunofluorescent antibody test (IFAT), the positive coincidence rate of the ELISA based on rTgGRA54 was 100% (72/72) and the negative coincidence rate was 80.95% (17/21). The indirect ELISA method based on TgGRA54 recombinant protein was established to detect T. gondii antibodies in bovine sera, and the recombinant protein reacted well with T. gondii positive sera from sheep, mouse, and swine, indicating that the recombinant protein is a good diagnostic antigen for T. gondii.
Assuntos
Coccidiose , Neospora , Toxoplasma , Toxoplasmose Animal , Toxoplasmose , Animais , Bovinos , Ovinos , Camundongos , Suínos , Toxoplasma/genética , Neospora/genética , Coccidiose/diagnóstico , Coccidiose/veterinária , Anticorpos Antiprotozoários , Toxoplasmose/diagnóstico , Toxoplasmose/prevenção & controle , Ensaio de Imunoadsorção Enzimática/veterinária , Proteínas Recombinantes/genética , Estudos Soroepidemiológicos , Toxoplasmose Animal/diagnóstico , Toxoplasmose Animal/parasitologiaRESUMO
Toxoplasma gondii is an intracellular parasitic organism affecting all warm-blooded vertebrates. Due to the unavailability of commercialized human T. gondii vaccine, many studies have been reported investigating the protective efficacy of pre-clinical T. gondii vaccines expressing diverse antigens. Careful antigen selection and implementing multifarious immunization strategies could enhance protection against toxoplasmosis in animal models. Although none of the available vaccines could remove the tissue-dwelling parasites from the host organism, findings from these pre-clinical toxoplasmosis vaccine studies highlighted their developmental potential and provided insights into rational vaccine design. We herein explored the progress of T. gondii vaccine development using DNA, protein subunit, and virus-like particle vaccine platforms. Specifically, we summarized the findings from the pre-clinical toxoplasmosis vaccine studies involving T. gondii challenge infection in mice published in the past 5 years.
Assuntos
Toxoplasma , Toxoplasmose , Humanos , Animais , Camundongos , Etnicidade , Imunização , Desenvolvimento de Vacinas , Toxoplasmose/prevenção & controleRESUMO
Toxoplasma gondii, a highly prevalent apicomplexan pathogen, can cause serious or even fatal toxoplasmosis in both animals and humans. Immunoprophylaxis is considered a promising strategy for controlling this disease. Calreticulin (CRT) is known as a pleiotropic protein, which is critical for calcium storage and phagocytosis of apoptotic cells. Our study examined the protective effects of recombinant T. gondii Calreticulin (rTgCRT) as a recombinant subunit vaccine against the T. gondii challenge in mice. Here, rTgCRT was successfully expressed in vitro using prokaryptic expression system. Polyclonal antibody (pAb) has been prepared by immunizing Sprague Dawley rats with rTgCRT. Western blotting showed that rTgCRT and natural TgCRT protein were recognized by serum of T. gondii infected mice and rTgCRT pAb, respectively. T lymphocyte subsets and antibody response were monitored using flow cytometry and enzyme-linked immunosorbent assay (ELISA). The results showed that ISA 201 rTgCRT could stimulate lymphocyte proliferation and induce high levels of total and subclasses of IgG. After the RH strain challenge, a longer survival period was given by the ISA 201 rTgCRT vaccine compared to the control groups; after infection with the PRU strain, we observed a 100% survival rate and a significant reduction in cysts load and size. In the neutralization test, high concentrations of rat-rTgCRT pAb provided 100% protection, while in the passive immunization trial, only weak protection was observed after RH challenge, indicating that rTgCRT pAb needs further modification to improve its activity in vivo. Taken together, these data confirmed that rTgCRT can trigger strong cellular and humoral immune responses against acute and chronic toxoplasmosis.
Assuntos
Vacinas Protozoárias , Toxoplasma , Toxoplasmose Animal , Toxoplasmose , Humanos , Camundongos , Ratos , Animais , Calreticulina/genética , Calreticulina/farmacologia , Proteínas de Protozoários , Imunidade Celular , Ratos Sprague-Dawley , Toxoplasmose/prevenção & controle , Proteínas Recombinantes/genética , Toxoplasmose Animal/prevenção & controle , Anticorpos AntiprotozoáriosRESUMO
Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis. It has been shown that the severity of symptoms depends on the functioning of the host immune system. Although T. gondii infection typically does not lead to severe disease in healthy people and after infection, it induces a stable immunity, but it can contribute to severe and even lethal Toxoplasmosis in immunocompromised individuals (AIDS, bone marrow transplant and neoplasia). The antigens that have been proposed to be used in vaccine candidate in various studies include surface antigens and secretory excretions that have been synthesized and evaluated in different studies. In some studies, secretory antigens play an important role in stimulating the host immune response. Various antigens such as SAG, GRA, ROP, ROM, and MAG have been from different strains of T. gondii have been synthesized and their protective effects have been evaluated in animal models in different vaccine platforms including recombinant antigens, nanoparticles, and DNA vaccine. Four bibliographic databases including Science Direct, PubMed Central (PMC), Scopus, and Google Scholar were searched for articles published up to 2020.The current review article focuses on recent studies on the use and usefulness of recombinant antigens, nanoparticles, and DNA vaccines.
Assuntos
Vacinas Protozoárias , Toxoplasma , Toxoplasmose , Vacinas de DNA , Animais , Humanos , Camundongos , Toxoplasma/genética , Antígenos de Protozoários/genética , Proteínas de Protozoários/genética , Vacinas Protozoárias/uso terapêutico , Vacinas Protozoárias/genética , Toxoplasmose/prevenção & controle , Toxoplasmose/parasitologia , Vacinas de DNA/uso terapêutico , Vacinas de DNA/genética , Camundongos Endogâmicos BALB CRESUMO
Raising awareness about Toxoplasma gondii infection among cat owners in Bangladesh is indispensable to formulate persuasive management tactics to avoid zoonotic infections from pet cats. However, to the authors' best knowledge, no studies have been performed in Bangladesh to determine knowledge and practices of toxoplasmosis in cat owners. Therefore, the objectives of the current study were to cover this research gap. We carried out a cross-sectional study in Bangladesh from June 2020 through December 2021. A structured online questionnaire was distributed to cat owners, which were voluntarily completed by them. The questionnaire included socio-demographic data, aetiology, transmissions, clinical signs, and preventive practices towards toxoplasmosis. Overall, 1,019 cat owners participated voluntarily in the cross-sectional survey. Among them, 793 (77.82%) participants showed poor knowledge regarding toxoplasmosis. Under specific knowledge sections, 62.51% of the participants revealed incorrect knowledge that toxoplasmosis was a zoonotic disease. In the same way, (72.03-85.77) % of the cat owners were unaware that the disease could be transmitted from improperly washed vegetables, raw or undercooked meat and fish, and contaminated water and milk with cat faeces. Respondents' age, education, occupation, residence type, and marital status were significantly (p < .05) associated with their knowledge level. Besides, 94.11% of cat owners had a good practice level. They followed good practices in different issues; however, they practiced those activities without knowing their impacts on disease control. Cat owners' age, education, occupation, and residence type had a significant (p < .05) association with the practice level against toxoplasmosis. This is the first study highlighting the low level of knowledge among cat owners about toxoplasmosis in Bangladesh. These knowledge gaps could increase the risk and transmission of Toxoplasma gondii infection among them and their families. The survey recommends the arrangement of educational training and programmes to increase the awareness of toxoplasmosis among cat owners.