RESUMEN
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.
Asunto(s)
Anticuerpos Antiprotozoarios , Proteínas Protozoarias , Vacunas Antiprotozoos , Toxoplasma , Toxoplasmosis Animal , Vacunas Atenuadas , Animales , Toxoplasma/inmunología , Toxoplasma/genética , Ratones , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/administración & dosificación , Vacunas Atenuadas/inmunología , Vacunas Atenuadas/administración & dosificación , Proteínas Protozoarias/inmunología , Proteínas Protozoarias/genética , Anticuerpos Antiprotozoarios/sangre , Femenino , Toxoplasmosis Animal/prevención & control , Toxoplasmosis Animal/inmunología , Citocinas/metabolismo , Virulencia , Carga de Parásitos , Modelos Animales de Enfermedad , Enfermedad Crónica , Toxoplasmosis/prevención & control , Toxoplasmosis/inmunología , Toxoplasmosis/parasitologíaRESUMEN
Entamoeba histolytica, the causative agent of amebiasis, is one of the top three parasitic causes of mortality worldwide. However, no vaccine exists against amebiasis. Using a lead candidate vaccine containing the LecA fragment of Gal-lectin and GLA-3M-052 liposome adjuvant, we immunized rhesus macaques via intranasal or intramuscular routes. The vaccine elicited high-avidity functional humoral responses as seen by the inhibition of amebic attachment to mammalian target cells by plasma and stool antibodies. Importantly, antigen-specific IFN-γ-secreting peripheral blood mononuclear cells (PBMCs) and IgG/IgA memory B cells (BMEM) were detected in immunized animals. Furthermore, antigen-specific antibody and cellular responses were maintained for at least 8 months after the final immunization as observed by robust LecA-specific BMEM as well as IFN-γ+ PBMC responses. Overall, both intranasal and intramuscular immunizations elicited a durable and functional response in systemic and mucosal compartments, which supports advancing the LecA+GLA-3M-052 liposome vaccine candidate to clinical testing.
Asunto(s)
Administración Intranasal , Anticuerpos Antiprotozoarios , Entamoeba histolytica , Entamebiasis , Interferón gamma , Leucocitos Mononucleares , Liposomas , Macaca mulatta , Vacunas Antiprotozoos , Animales , Entamoeba histolytica/inmunología , Liposomas/inmunología , Liposomas/administración & dosificación , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/administración & dosificación , Anticuerpos Antiprotozoarios/sangre , Anticuerpos Antiprotozoarios/inmunología , Leucocitos Mononucleares/inmunología , Entamebiasis/prevención & control , Entamebiasis/inmunología , Interferón gamma/inmunología , Interferón gamma/metabolismo , Inyecciones Intramusculares , Inmunogenicidad Vacunal , Adyuvantes de Vacunas/administración & dosificación , Adyuvantes Inmunológicos/administración & dosificación , Linfocitos B/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Inmunoglobulina A/inmunología , Inmunoglobulina A/sangre , Antígenos de Protozoos/inmunología , Inmunidad Humoral , Memoria Inmunológica , Proteínas Protozoarias/inmunologíaRESUMEN
Toxoplasma gondii is an important protozoan pathogen, which can cause severe diseases in the newborns and immunocompromised individuals. Developing an effective vaccine against Toxoplasma infection is a critically important global health priority. Immunofluorescence staining analysis revealed that TgSAG2 and TgSRS2 are membrane associated and displayed on the surface of the parasite. Immunizations with pBud-SAG2, pBud-SRS2 and pBud-SAG2-SRS2 DNA vaccines significantly increased the production of specific IgG antibodies. Immunization with pBud-SAG2-SRS2 elicited cellular immune response with higher concentrations of IFN-γ and IL-4 compared to the control group. Antigen-specific lymphocyte proliferations in the pBud-SRS2 and pBud-SAG2-SRS2 groups were significantly higher compared to that in the control group. Furthermore, 30 % of mice immunized with pBud-SAG2-SRS2 survived after the challenge infection with virulent T. gondii RH tachyzoites. This study revealed that immunization with pBud-SAG2-SRS2 induced potent immune responses, and has the potential as a promising vaccine candidate for the control of T. gondii infection.
Asunto(s)
Anticuerpos Antiprotozoarios , Antígenos de Protozoos , Inmunoglobulina G , Proteínas Protozoarias , Vacunas Antiprotozoos , Toxoplasma , Toxoplasmosis Animal , Vacunas de ADN , Animales , Vacunas de ADN/inmunología , Vacunas de ADN/genética , Vacunas de ADN/administración & dosificación , Antígenos de Protozoos/inmunología , Antígenos de Protozoos/genética , Proteínas Protozoarias/inmunología , Proteínas Protozoarias/genética , Toxoplasma/inmunología , Toxoplasma/genética , Anticuerpos Antiprotozoarios/sangre , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/administración & dosificación , Vacunas Antiprotozoos/genética , Ratones , Inmunoglobulina G/sangre , Femenino , Toxoplasmosis Animal/prevención & control , Toxoplasmosis Animal/inmunología , Ratones Endogámicos BALB C , Interferón gamma/inmunología , Modelos Animales de Enfermedad , Proliferación Celular , Interleucina-4/inmunología , Análisis de SupervivenciaRESUMEN
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.
Asunto(s)
Anticuerpos Antiprotozoarios , Electroporación , Ratones Endogámicos BALB C , Proteínas Protozoarias , Vacunas Antiprotozoos , Toxoplasma , Vacunas de ADN , Vacunas de ADN/inmunología , Vacunas de ADN/administración & dosificación , Animales , Toxoplasma/inmunología , Toxoplasma/genética , Anticuerpos Antiprotozoarios/sangre , Anticuerpos Antiprotozoarios/inmunología , Electroporación/métodos , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/administración & dosificación , Proteínas Protozoarias/inmunología , Proteínas Protozoarias/genética , Ratones , Femenino , Toxoplasmosis Animal/prevención & control , Toxoplasmosis Animal/inmunología , Inmunoglobulina G/sangre , Toxoplasmosis/prevención & control , Toxoplasmosis/inmunología , Antígenos de Protozoos/inmunología , Antígenos de Protozoos/genética , Interferón gamma/inmunología , Linfocitos T CD8-positivos/inmunologíaRESUMEN
BACKGROUND: Chicken coccidiosis is a protozoan disease that leads to considerable economic losses in the poultry industry. Live oocyst vaccination is currently the most effective measure for the prevention of coccidiosis. However, it provides limited protection with several drawbacks, such as poor immunological protection and potential reversion to virulence. Therefore, the development of effective and safe vaccines against chicken coccidiosis is still urgently needed. METHODS: In this study, a novel oral vaccine against Eimeria tenella was developed by constructing a recombinant Lactobacillus plantarum (NC8) strain expressing the E. tenella RON2 protein. We administered recombinant L. plantarum orally at 3, 4 and 5 days of age and again at 17, 18 and 19 days of age. Meanwhile, each chick in the commercial vaccine group was immunized with 3 × 102 live oocysts of coccidia. A total of 5 × 104 sporulated oocysts of E. tenella were inoculated in each chicken at 30 days. Then, the immunoprotection effect was evaluated after E. tenella infection. RESULTS: The results showed that the proportion of CD4+ and CD8+ T cells, the proliferative ability of spleen lymphocytes, inflammatory cytokine levels and specific antibody titers of chicks immunized with recombinant L. plantarum were significantly increased (P < 0.05). The relative body weight gains were increased and the number of oocysts per gram (OPG) was decreased after E. tenella challenge. Moreover, the lesion scores and histopathological cecum sections showed that recombinant L. plantarum can significantly relieve pathological damage in the cecum. The ACI was 170.89 in the recombinant L. plantarum group, which was higher than the 150.14 in the commercial vaccine group. CONCLUSIONS: These above results indicate that L. plantarum expressing RON2 improved humoral and cellular immunity and enhanced immunoprotection against E. tenella. The protective efficacy was superior to that of vaccination with the commercial live oocyst vaccine. This study suggests that recombinant L. plantarum expressing the RON2 protein provides a promising strategy for vaccine development against coccidiosis.
Asunto(s)
Pollos , Coccidiosis , Eimeria tenella , Lactobacillus plantarum , Enfermedades de las Aves de Corral , Proteínas Protozoarias , Vacunas Antiprotozoos , Vacunación , Animales , Eimeria tenella/inmunología , Eimeria tenella/genética , Coccidiosis/prevención & control , Coccidiosis/veterinaria , Coccidiosis/inmunología , Enfermedades de las Aves de Corral/prevención & control , Enfermedades de las Aves de Corral/parasitología , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/genética , Vacunas Antiprotozoos/administración & dosificación , Lactobacillus plantarum/genética , Lactobacillus plantarum/inmunología , Administración Oral , Proteínas Protozoarias/inmunología , Proteínas Protozoarias/genética , Vacunación/veterinaria , Anticuerpos Antiprotozoarios/sangre , Vacunas Sintéticas/inmunología , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/genéticaRESUMEN
Neosporosis is the major infectious cause of abortion and reproductive losses in cattle worldwide; however, there are no available vaccines or drugs to control this disease. Recently, a dual (positive and negative) DIVA-like (Differentiation of Infected from Vaccinated Animals) vaccine was evaluated in a pregnant mouse model of neosporosis, showing promising immunogenic and protective results. The current report aimed to study the safety, the dose-dependent immunogenicity and the dual DIVA-like character of a recombinant subunit vaccine composed of the major surface antigen from Neospora caninum (rNcSAG1) and the carrier/adjuvant Heat shock protein 81.2 from Arabidopsis thaliana (rAtHsp81.2) in cattle. Healthy heifers were separated and assigned to experimental groups A-F and subcutaneously immunized with 2 doses of vaccine formulations 30 days apart as follows: A (n = 4): 50 µg rNcSAG1 + 150 µg rAtHsp81.2; B (n = 4): 200 µg rNcSAG1 + 600 µg rAtHsp81.2; C (n = 4): 500 µg rNcSAG1 + 1,500 µg rAtHsp81.2; D (n = 3): 150 µg rAtHsp81.2; E (n = 3):1,500 µg rAtHsp81.2, and F (n = 3) 2 ml of sterile PBS. The immunization of heifers with the different vaccine or adjuvant doses (groups A-E) was demonstrated to be safe and did not modify the mean value of the evaluated serum biomarkers of metabolic function (GOT/ASP, GPT/ALT, UREA, Glucose and total proteins). The kinetics and magnitude of the immune responses were dose-dependent. The higher dose of the vaccine formulation (group C) stimulated a broad and potent humoral and cellular immune response, characterized by an IgG1/IgG2 isotype profile and IFN-γ secretion. In addition, this was the first time that dual DIVA-like character of a vaccine against neosporosis was demonstrated, allowing us to differentiate vaccinated from infected heifers by two different DIVA compliant test approaches. These results encourage us to evaluate its protective efficacy in infected pregnant cattle in the future.
Asunto(s)
Enfermedades de los Bovinos , Coccidiosis , Neospora , Vacunas Antiprotozoos , Vacunas Sintéticas , Animales , Bovinos , Coccidiosis/prevención & control , Coccidiosis/veterinaria , Coccidiosis/inmunología , Enfermedades de los Bovinos/prevención & control , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Neospora/inmunología , Femenino , Vacunas Sintéticas/inmunología , Vacunas Sintéticas/administración & dosificación , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/administración & dosificación , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/inmunología , Proteínas Protozoarias/inmunología , Vacunas de Subunidad/inmunología , Vacunas de Subunidad/administración & dosificación , Inmunogenicidad Vacunal , EmbarazoRESUMEN
The increasing significance of the aquaculture sector and commercially valuable species underscores the need to develop alternatives for controlling diseases such as Ichthyophthirius multifiliis-induced ichthyophthiriasis. This ciliated protozoan parasite threatens nearly all freshwater fish species, causing substantial losses in the fishery industry. Despite this, effective large-scale treatments are lacking, emphasizing the necessity of adopting preventive strategies. While the pathogenesis of ichthyophthiriasis and its immune stimulation allows for vaccination strategies, precise adjustments are crucial to ensure the production of an effective vaccine compound. Therefore, this study aimed to evaluate the impact of immunizing Astyanax lacustris with a genetic vaccine containing IAG52A from I. multifiliis and the molecular adjuvant IL-8 from A. lacustris. Transcript analysis in immunized A. lacustris indicated mRNA production in fish muscles, demonstrating an expression of this mRNA. Fish were divided into five groups, receiving different vaccine formulations, and all groups received a booster dose 14 days after the initial immunization. Samples from vaccinated fish showed increased IL-1ß mRNA expression in the spleen within 6 h post the second dose and after 14 days. In the head kidney, IL-1ß mRNA expression showed no significant difference at 6 and 24 h but an increase was noted in fish injected with IAG and IAG + IL-8 after 14 days. IL-8 mRNA expression in the spleen and kidney did not significantly differ from the control group. Histological analysis revealed no variation in leukocyte concentration at 6 and 24 h post-vaccination; however, after 14 days, the groups injected with IAG and IAG + IL-8 exhibited a higher leukocyte density at the application sites than the control. The obtained data suggest that the used vaccine is transcribed, indicating its potential to stimulate innate immune response parameters through mRNA cytokine expression and leukocyte migration.
Asunto(s)
Adyuvantes Inmunológicos , Infecciones por Cilióforos , Enfermedades de los Peces , Hymenostomatida , Vacunas de ADN , Animales , Enfermedades de los Peces/prevención & control , Enfermedades de los Peces/inmunología , Enfermedades de los Peces/parasitología , Infecciones por Cilióforos/veterinaria , Infecciones por Cilióforos/prevención & control , Infecciones por Cilióforos/inmunología , Hymenostomatida/inmunología , Vacunas de ADN/inmunología , Vacunas de ADN/administración & dosificación , Adyuvantes Inmunológicos/administración & dosificación , Vacunación/veterinaria , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/administración & dosificación , Characidae/inmunología , Interleucinas/inmunologíaRESUMEN
Chicken coccidiosis has inflicted significant economic losses upon the poultry industry. The primary strategies for preventing and controlling chicken coccidiosis include anticoccidial drugs and vaccination. However, these approaches face limitations, such as drug residues and resistance associated with anticoccidial drugs, and safety concerns related to live vaccines. Consequently, the urgent development of innovative vaccines, such as subunit vaccines, is imperative. In previous study, we screened 2 candidate antigens: Eimeria maxima lysophospholipase (EmLPL) and E. maxima regulatory T cell inducing molecule 1 (EmTregIM-1). To investigate the immune protective effect of the 2 candidate antigens against Eimeria maxima (E. maxima) infection, we constructed recombinant plasmids, namely pET-28a-EmLPL and pET-28a-EmTregIM-1, proceeded to induce the expression of recombinant proteins of EmLPL (rEmLPL) and EmTregIM-1 (rEmTregIM-1). The immunogenic properties of these proteins were confirmed through western blot analysis. Targeting EmLPL and EmTregIM-1, we developed subunit vaccines and encapsulated them in PLGA nanoparticles, resulting in nano-vaccines: PLGA-rEmLPL and PLGA-rEmTregIM-1. The efficacy of these vaccines was assessed through animal protection experiments. The results demonstrated that rEmLPL and rEmTregIM-1 were successfully recognized by anti-E. maxima chicken sera and His-conjugated mouse monoclonal antibodies. Immunization with both subunit and nano-vaccines containing EmLPL and EmTregIM-1 markedly mitigated weight loss and reduced oocyst shedding in chickens infected with E. maxima. Furthermore, the anticoccidial indexes (ACI) for both rEmLPL and PLGA-rEmLPL exceeded 160, whereas those for rEmTregIM-1 and PLGA-rEmTregIM-1 were above 120 but did not reach 160, indicating superior protective efficacy of the rEmLPL and PLGA-rEmLPL formulations. By contrast, the protection afforded by rEmTregIM-1 and PLGA-rEmTregIM-1 was comparatively lower. Thus, EmLPL is identified as a promising candidate antigen for vaccine development against E. maxima infection.
Asunto(s)
Pollos , Coccidiosis , Eimeria , Enfermedades de las Aves de Corral , Vacunas Antiprotozoos , Animales , Eimeria/inmunología , Coccidiosis/veterinaria , Coccidiosis/prevención & control , Coccidiosis/inmunología , Coccidiosis/parasitología , Enfermedades de las Aves de Corral/prevención & control , Enfermedades de las Aves de Corral/parasitología , Enfermedades de las Aves de Corral/inmunología , Vacunas Antiprotozoos/inmunología , Vacunas Antiprotozoos/administración & dosificación , Vacunas de Subunidad/administración & dosificación , Vacunas de Subunidad/inmunología , Antígenos de Protozoos/inmunologíaRESUMEN
This study compared 2 herbal anticoccidiosis drugs (water-soluble and feed-additive drugs) with monensin coccidiostat, toltrazuril (TTZ, anticoccidiosis drug), and Livacox Q (anticoccidiosis vaccine) in terms of their effects on the prevention and treatment of coccidiosis in broilers. In this study, 280 Ross 308 broiler chickens (a mix of both genders) were used in a completely randomized design with 7 treatments and 5 replications each including 8 chickens per replicate. On d 21 of rearing, all experimental groups, except for the negative control group (NC), were challenged with a mixed suspension of common strains of Eimeria, and the intended indices were assessed, including performance indices, number of oocysts per gram (OPG) of feces, intestinal injuries, and the total number of intestinal bacteria. In addition, the NC and the group receiving the monensin had greater body weight gain (BWG) (P < 0.05). At the end of week 6, the monensin group had the highest feed intake (FI), while the water soluble medicine treatment resulted in the lowest feed intake (P < 0.05). Regarding the lesion scores on day 28, the highest and lowest rates of jejunal injuries were observed in the positive control group (PC), the monensin and vaccine group respectively. The rate of oocysts excretion (oocysts per gram of feces = OPG) on different days was higher in the PC group, and the use of monensin could further reduce excretion compared to the other groups (P > 0.05). Based on a comparison of the population of lactic acid bacteria between the NC and both medicinal plant treated groups, the use of these products could increase the population of these types of bacteria. Moreover, the population of Escherichia coli was less considerable in the NC and herbal powder groups (P < 0.05). Overall, similar to commercial medicines, the herbal medicines used in this project can be effective in the prevention and treatment of coccidiosis and can improve profitability in broiler rearing centers by improving intestinal health.
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Alimentación Animal , Pollos , Coccidiosis , Coccidiostáticos , Dieta , Eimeria , Enfermedades de las Aves de Corral , Vacunas Antiprotozoos , Triazinas , Animales , Coccidiosis/veterinaria , Coccidiosis/prevención & control , Coccidiosis/parasitología , Coccidiostáticos/farmacología , Coccidiostáticos/administración & dosificación , Enfermedades de las Aves de Corral/prevención & control , Enfermedades de las Aves de Corral/parasitología , Triazinas/farmacología , Triazinas/administración & dosificación , Alimentación Animal/análisis , Masculino , Vacunas Antiprotozoos/administración & dosificación , Vacunas Antiprotozoos/farmacología , Eimeria/fisiología , Femenino , Dieta/veterinaria , Distribución Aleatoria , Suplementos Dietéticos/análisisRESUMEN
Toxoplasma gondii (T. gondii) is an intracellular parasitic protozoan that can cause serious public health problems. However, there is no effectively preventive or therapeutic strategy available for human and animals. In the present study, we developed a DNA vaccine encoding T. gondii oxidoreductase from short-chain dehydrogenase/reductase family (TgSDRO-pVAX1) and then entrapped in chitosan and poly lactic-co-glycolic acid (PLGA) to improve the efficacy. When encapsulated in chitosan (TgSDRO-pVAX1/CS nanospheres) and PLGA (TgSDRO-pVAX1/PLGA nanospheres), adequate plasmids were loaded and released stably. Before animal immunizations, the DNA vaccine was transfected into HEK 293-T cells and examined by western blotting and laser confocal microscopy. Th1/Th2 cellular and humoral immunity was induced in immunized mice, accompanied by modulated secretion of antibodies and cytokines, promoted the maturation and MHC expression of dendritic cells, and enhanced the percentages of CD4+ and CD8+ T lymphocytes. Immunization with TgSDRO-pVAX1/CS and TgSDRO-pVAX1/PLGA nanospheres conferred significant immunity with lower parasite burden in the mice model of acute toxoplasmosis. Furthermore, our results also lent credit to the idea that TgSDRO-pVAX1/CS and TgSDRO-pVAX1/PLGA nanospheres are substitutes for each other. In general, the current study proposed that TgSDRO-pVAX1 with chitosan or PLGA as the delivery vehicle is a promising vaccine candidate against acute toxoplasmosis.
Asunto(s)
Antígenos de Protozoos/administración & dosificación , Quitosano/administración & dosificación , Nanosferas/administración & dosificación , Oxidorreductasas/administración & dosificación , Copolímero de Ácido Poliláctico-Ácido Poliglicólico/administración & dosificación , Proteínas Protozoarias/administración & dosificación , Vacunas Antiprotozoos/administración & dosificación , Toxoplasmosis Animal/prevención & control , Vacunas de ADN/administración & dosificación , Animales , Anticuerpos Antiprotozoarios/inmunología , Antígenos de Protozoos/genética , Células Dendríticas/inmunología , Femenino , Células HEK293 , Humanos , Inmunoglobulina G/inmunología , Linfocitos/inmunología , Ratones Endogámicos BALB C , Oxidorreductasas/genética , Plásmidos , Proteínas Protozoarias/genética , Ratas Sprague-Dawley , Toxoplasma/inmunologíaRESUMEN
With growing cross-disciplinary collaboration among researchers, it is increasingly important to record detailed methodology to prevent the repetition of preliminary experiments. The purpose of this paper is to explain the development of a coccidiosis challenge model for the investigation of dietary interventions to coccidiosis in broiler chickens. The objectives are to select a dose of mixed species coccidial vaccine and evaluate the suitability (ability to produce a consistent, marked change) of selected response variables important to nutritional studies at different times postinfection (PI). Coccivac-B and Coccivac-B52 (Merck Animal Health) were evaluated as the source of coccidia in three trials. Trials 1 and 2 were randomized complete block designs with four doses (0, 10, 20, or 30 times (×) label dose) of Coccivac-B administered to 12 replicate cages of six birds by repeater pipette (Trial 1) or gavaging needle (Trial 2). Trial 3 used a completely randomized design with 0× or 30× label dose of Coccivac-B52 administered by gavaging needle to six replicate cages of six birds. Birds were gavaged at 15 days of age, and response criteria were evaluated 7 days PI in all trials and again at 10 days PI in Trials 1 and 2. All means are reported in order of increasing coccidia dose with significance accepted at P ≤ 0.05. Broiler performance was not affected by coccidia in Trials 1 or 3 but grew poorer with increasing dose from 0 to 7 days PI in Trial 2 (body weight gain, 465, 421, 388, 365 g; feed to gain, 1.37, 1.47, 1.52, 1.58). As coccidia dose increased, nitrogen corrected apparent metabolizable energy decreased (Trial 1, 3387, 3318, 3267, 3170 kcal kg-1; Trial 2, 3358, 2535, 2422, 2309 kcal kg-1; Trial 3, not measured), while relative weight, length, and content for intestinal sections increased (Trials 1through 3). Gross lesion (duodenum, jejunum/ileum, ceca) and oocyst count scores (jejunum/ileum, ceca) increased with dose; however, gross scoring often suggested infection in unchallenged birds, a finding unsupported by oocyst count scores. At 7 days PI there was no correlation between midgut gross lesion score and midgut oocyst count score (r = 0.06, P = 0.705), but cecal scores were weakly correlated (r = 0.55, P < 0.001). Administering coccidia via repeater pipette (Trial 1) resulted in respiratory distress in some birds, while use of the gavaging needle (Trials 2 and 3) successfully induced intestinal damage in chickens without resulting in coccidia related mortality. Thirty times the label dose at 7 days PI resulted in the greatest number of response variables that produced a consistent, marked change. Therefore, consideration should be given to these conditions when designing future coccidiosis challenge models using vaccines as a source of coccidia.
Artículo regularDesarrollo de un modelo de desafío para coccidiosis utilizando una vacuna de ooquistes vivos disponible comercialmente. Con la creciente colaboración interdisciplinaria entre investigadores, es cada vez más importante registrar la metodología detallada para evitar la repetición de experimentos preliminares. El propósito de este artículo es explicar el desarrollo de un modelo de desafío de coccidiosis para la investigación de intervenciones dietéticas para coccidiosis en pollos de engorde. Los objetivos son seleccionar una dosis de vacuna coccidial de especies mixtas y evaluar la idoneidad (capacidad de producir un cambio marcado y consistente) de las variables de respuesta seleccionadas que son importantes para los estudios nutricionales en diferentes momentos posteriores a la infección (PI). Las vacunas Coccivac-B o Coccivac B-52 (Merck Animal Health) se evaluaron como fuente de coccidias en tres ensayos. Los ensayos 1 y 2 fueron diseños de bloques completamente aleatorios con cuatro dosis (0, 10, 20 o 30 veces (×) la dosis indicada en la etiqueta) de Coccivac-B administradas a 12 jaulas repetidas de seis aves mediante una pipeta repetidora (ensayo 1) o por sonda oral. (Prueba 2). El ensayo 3 utilizó un diseño completamente aleatorio con una dosis de etiqueta de 0 × o 30 × de Coccivac-B52 administrada con una sonda oral en seis jaulas repetidas de seis aves. Las aves fueron inoculadas por sonda a los 15 días de edad y los criterios de respuesta se evaluaron a los 7 días postinoculación en todos los ensayos y nuevamente a los 10 días postinoculación en los ensayos 1 y 2. Todos los promedios se reportan en orden de dosis crecientes de coccidias con significancia aceptada en P ≤ 0.05. El rendimiento de los pollos de engorde no se vio afectado por las coccidias en los Ensayos 1 o 3, pero empeoró al aumentar la dosis de los cero a 7 días después de la inoculación en el Ensayo 2 (aumento de peso corporal, 465, 421, 388, 365 g; alimento para ganar, 1.37, 1.47, 1.52, 1.58). A medida que aumentaba la dosis de coccidia, la energía metabolizable de nitrógeno aparente y corregida disminuyó (Prueba 1, 3387, 3318, 3267, 3170 kcal kg-1; Prueba 2, 3358, 2535, 2422, 2309 kcal kg-1; Prueba 3, no medida), mientras que el peso relativo, la longitud y el contenido de las secciones intestinales aumentaron (ensayos 1 a 3). La lesión macroscópica (duodeno, yeyuno/íleon, ciego) y las puntuaciones del recuento de oocistos (yeyuno/íleon, ciego) aumentaron con la dosis; sin embargo, la puntuación bruta a menudo sugirió infección en aves no desafiadas, un hallazgo que no está respaldado por las puntuaciones del recuento de ooquistes. A los 7 días después de la infección no hubo correlación entre la puntuación de la lesión macroscópica del intestino medio y la puntuación del recuento de oocistos del intestino medio (r= 0,06, P= 0,705), pero las puntuaciones cecales se correlacionaron débilmente (r = 0.55, P <0.001). La administración de coccidias a través de una pipeta repetidora (Ensayo 1) provocó dificultad respiratoria en algunas aves, mientras que el uso de la sonda oral (Ensayos 2 y 3) indujo con éxito el daño intestinal en los pollos sin dar como resultado mortalidad relacionada con los coccidias. Treinta veces la dosis de la etiqueta a los 7 días después de la infección resultó en el mayor número de variables de respuesta que produjeron un cambio marcado y consistente. Por lo tanto, deben tenerse en cuenta estas condiciones al diseñar futuros modelos de exposición a la coccidiosis que utilicen vacunas como fuente de coccidias.
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Pollos , Coccidiosis/veterinaria , Eimeria/inmunología , Enfermedades de las Aves de Corral/prevención & control , Vacunas Antiprotozoos/administración & dosificación , Alimentación Animal/análisis , Animales , Coccidiosis/parasitología , Coccidiosis/prevención & control , Dieta/veterinaria , Suplementos Dietéticos , Masculino , Oocistos , Enfermedades de las Aves de Corral/parasitología , Vacunas Atenuadas/administración & dosificaciónRESUMEN
Amebiasis is a neglected tropical disease caused by Entamoeba histolytica. Although the disease burden varies geographically, amebiasis is estimated to account for some 55,000 deaths and millions of infections globally per year. Children and travelers are among the groups with the greatest risk of infection. There are currently no licensed vaccines for prevention of amebiasis, although key immune correlates for protection have been proposed from observational studies in humans. We previously described the development of a liposomal adjuvant formulation containing two synthetic TLR ligands (GLA and 3M-052) that enhanced antigen-specific fecal IgA, serum IgG2a, a mixed IFNγ and IL-17A cytokine profile from splenocytes, and protective efficacy following intranasal administration with the LecA antigen. By applying a statistical design of experiments (DOE) and desirability function approach, we now describe the optimization of the dose of each vaccine formulation component (LecA, GLA, 3M-052, and liposome) as well as the excipient composition (acyl chain length and saturation; PEGylated lipid:phospholipid ratio; and presence of antioxidant, tonicity, or viscosity agents) to maximize desired immunogenicity characteristics while maintaining physicochemical stability. This DOE/desirability index approach led to the identification of a lead candidate composition that demonstrated immune response durability and protective efficacy in the mouse model, as well as an assessment of the impact of each active vaccine formulation component on protection. Thus, we demonstrate that both GLA and 3M-052 are required for statistically significant protective efficacy. We also show that immunogenicity and efficacy results differ in female vs male mice, and the differences appear to be at least partly associated with adjuvant formulation composition.
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Antígenos de Protozoos/inmunología , Entamoeba histolytica/inmunología , Entamebiasis/inmunología , Entamebiasis/prevención & control , Vacunas Antiprotozoos/inmunología , Adyuvantes Inmunológicos/química , Administración Intranasal , Animales , Anticuerpos Antiprotozoarios/sangre , Anticuerpos Antiprotozoarios/inmunología , Fenómenos Químicos , Citocinas/metabolismo , Composición de Medicamentos , Entamebiasis/parasitología , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunogenicidad Vacunal , Inmunoglobulina G/inmunología , Liposomas , Ratones , Vacunas Antiprotozoos/administración & dosificación , Vacunas Antiprotozoos/química , VacunaciónRESUMEN
Despite the enormous morbidity attributed to schistosomiasis, there is still no vaccine to combat the disease for the hundreds of millions of infected people. The anthelmintic drug, praziquantel, is the mainstay treatment option, although its molecular mechanism of action remains poorly defined. Praziquantel treatment damages the outermost surface of the parasite, the tegument, liberating surface antigens from dying worms that invoke a robust immune response which in some subjects results in immunologic resistance to reinfection. Herein we term this phenomenon Drug-Induced Vaccination (DIV). To identify the antigenic targets of DIV antibodies in urogenital schistosomiasis, we constructed a recombinant proteome array consisting of approximately 1,000 proteins informed by various secretome datasets including validated proteomes and bioinformatic predictions. Arrays were screened with sera from human subjects treated with praziquantel and shown 18 months later to be either reinfected (chronically infected subjects, CI) or resistant to reinfection (DIV). IgG responses to numerous antigens were significantly elevated in DIV compared to CI subjects, and indeed IgG responses to some antigens were completely undetectable in CI subjects but robustly recognized by DIV subjects. One antigen in particular, a cystatin cysteine protease inhibitor stood out as a unique target of DIV IgG, so recombinant cystatin was produced, and its vaccine efficacy assessed in a heterologous Schistosoma mansoni mouse challenge model. While there was no significant impact of vaccination with adjuvanted cystatin on adult worm numbers, highly significant reductions in liver egg burdens (45-55%, P<0.0001) and intestinal egg burdens (50-54%, P<0.0003) were achieved in mice vaccinated with cystatin in two independent trials. This study has revealed numerous antigens that are targets of DIV antibodies in urogenital schistosomiasis and offer promise as subunit vaccine targets for a drug-linked vaccination approach to controlling schistosomiasis.
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Antígenos Helmínticos/inmunología , Mapeo Epitopo , Interacciones Huésped-Patógeno/efectos de los fármacos , Interacciones Huésped-Patógeno/inmunología , Praziquantel/farmacología , Schistosoma haematobium/inmunología , Esquistosomiasis Urinaria/inmunología , Animales , Anticuerpos Antihelmínticos/inmunología , Biología Computacional/métodos , Modelos Animales de Enfermedad , Mapeo Epitopo/métodos , Proteínas del Helminto/inmunología , Humanos , Inmunización , Inmunoglobulina G/inmunología , Ratones , Carga de Parásitos , Proteómica/métodos , Vacunas Antiprotozoos/administración & dosificación , Vacunas Antiprotozoos/inmunología , Esquistosomiasis Urinaria/parasitología , Esquistosomiasis Urinaria/prevención & control , VacunaciónRESUMEN
Entamoeba histolytica is an intestinal parasite that causes dysentery and amebic liver abscess. E. histolytica has the capability to invade host tissue by union of virulence factor Gal/GalNAc lectin; this molecule induces an adherence-inhibitory antibody response as well as to protect against amebic liver abscess (ALA). The present work showed the effect of the immunization with PEΔIII-LC3-KDEL3 recombinant protein. In vitro, this candidate vaccine inhibited adherence of E. histolytica trophozoites to HepG2 cell monolayer, avoiding the cytolysis, and in a hamster model, we observed a vaccine-induced protection against the damage to tissue liver and the inhibition of uncontrolled inflammation. PEΔIII-LC3-KDEL3 reduced the expression of TNF-α, IL-1ß, and NF-κB in all immunized groups at 4- and 7-day postinfection. The levels of IL-10, FOXP3, and IFN-γ were elevated at 7 days. The immunohistochemistry assay confirmed this result, revealing an elevated quantity of +IFN-γ cells in the liver tissue. ALA formation in hamsters immunized was minimal, and few trophozoites were identified. Hence, immunization with PEΔIII-LC3-KDEL3 herein prevented invasive amebiasis, avoided an acute proinflammatory response, and activated a protective response within a short time. Finally, this recombinant protein induced an increase of serum IgG.
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Entamoeba histolytica/inmunología , Absceso Hepático Amebiano/prevención & control , Proteínas Protozoarias/administración & dosificación , Vacunas Antiprotozoos/administración & dosificación , Proteínas Recombinantes de Fusión/administración & dosificación , Animales , Anticuerpos Antiprotozoarios/sangre , Modelos Animales de Enfermedad , Entamoeba histolytica/genética , Humanos , Inmunogenicidad Vacunal , Lectinas/genética , Lectinas/inmunología , Hígado/inmunología , Hígado/parasitología , Hígado/patología , Absceso Hepático Amebiano/sangre , Absceso Hepático Amebiano/parasitología , Absceso Hepático Amebiano/patología , Masculino , Mesocricetus , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos/genética , Vacunas Antiprotozoos/inmunología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunologíaRESUMEN
BACKGROUND: Babesia bovis reproduces sexually in the gut of its tick vector Rhipicephalus microplus, which involves expression of 6cys A and 6cys B proteins. Members of the widely conserved 6cys superfamily are candidates for transmission blocking vaccines (TBV), but intricacies in the immunogenicity of the 6cys proteins in the related Plasmodium parasites required the identification of transmission blocking domains in these molecules for vaccine design. Hereby, the immunogenic efficacy of recombinant (r) B. bovis 6cys A and B proteins as a TBV formulation was studied. METHODS: The immunogenicity of r6cys A and 6cys B proteins expressed in a eukaryotic system was evaluated in a cattle immunization trial (3 immunized and 3 control calves). A B. bovis sexual stage induction in vitro inhibition assay to assess the ability of antibodies to block the production of sexual forms by the parasite was developed. RESULTS: Immunized cattle generated antibodies against r6cys A and r6cys B that were unable to block sexual reproduction of the parasite in ticks. Additionally, these antibodies also failed in recognizing native 6cys A and 6cys B and peptides representing 6cys A and 6cys B functional domains and in inhibiting the development of sexual forms in an in vitro induction system. In contrast, rabbit antibodies generated against synthetic peptides representing predicted B-cell epitopes of 6cys A and 6cys B recognized recombinant and native forms of both 6cys proteins as well as peptides representing 6cys A and 6cys B functional domains and were able to neutralize development of sexual forms of the parasite in vitro. CONCLUSIONS: These data, combined with similar work performed on Plasmodium 6cys proteins, indicate that an effective 6cys protein-based TBV against B. bovis will require identifying and targeting selected regions of proteins containing epitopes able to reduce transmission.
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Babesia bovis/inmunología , Babesiosis/prevención & control , Enfermedades de los Bovinos/prevención & control , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos/inmunología , Animales , Anticuerpos Antiprotozoarios/inmunología , Babesia bovis/genética , Babesia bovis/fisiología , Babesiosis/inmunología , Babesiosis/parasitología , Babesiosis/transmisión , Bovinos , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/transmisión , Evaluación Preclínica de Medicamentos , Femenino , Masculino , Proteínas Protozoarias/administración & dosificación , Proteínas Protozoarias/genética , Vacunas Antiprotozoos/administración & dosificación , Vacunas Antiprotozoos/genética , Conejos , Reproducción , Rhipicephalus/parasitología , Rhipicephalus/fisiologíaRESUMEN
In spite of several decades of research, an effective vaccine against schistosomiasis remains elusive. The radiation-attenuated (RA) cercarial vaccine is still the best model eliciting high protection levels, although the immune mechanisms have not yet been fully characterized. In order to identify genes and pathways underlying protection we investigated patterns of gene expression in PBMC and skin draining Lymph Nodes (LN) from mice using two exposure comparisons: vaccination with 500 attenuated cercariae versus infection with 500 normal cercariae; one versus three doses. Vaccinated mice were challenged with 120 normal parasites. Integration of PBMC and LN data from the infected group revealed early up-regulation of pathways associated with Th2 skewing and polarization of IgG antibody profiles. Additionally, hemostasis pathways were downregulated in infected mice, correlating with platelet reduction, potentially a mechanism to assist parasite migration through capillary beds. Conversely, up regulation of such mechanisms after vaccination may explain parasite blockade in the lungs. In contrast, a single exposure to attenuated parasites revealed early establishment of a Th1 bias (signaling of IL-1, IFN-γ; and Leishmania infection). Genes encoding chemokines and their receptors were more prominent in vaccinated mice, indicating an enhanced capacity for inflammation, potentially augmenting the inhibition of intravascular migration. Increasing the vaccinations from one to three did not dramatically elevate protection, but there was a clear shift towards antibody-mediated effectors. However, elements of the Th1 bias were still evident. Notable features after three vaccinations were markers of cytotoxicity (including IL-6 and NK cells) together with growth factors and their receptors (FGFR/VEGF/EGF) and the apoptosis pathway. Indeed, there is evidence for the development of anergy after three vaccinations, borne out by the limited responses detected in samples after challenge. We infer that persistence of a Th1 response puts a limit on expression of antibody-mediated mechanisms. This feature may explain the failure of multiple doses to drive protection towards sterile immunity. We suggest that the secretions of lung stage parasites would make a novel cohort of antigens for testing in protection experiments.
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Hemostasis , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Vacunas Antiprotozoos/administración & dosificación , Schistosoma mansoni/inmunología , Esquistosomiasis mansoni/prevención & control , Biología de Sistemas , Animales , Cercarias/inmunología , Modelos Animales de Enfermedad , Femenino , Perfilación de la Expresión Génica , Hemostasis/genética , Interacciones Huésped-Parásitos , Péptidos y Proteínas de Señalización Intercelular/genética , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/metabolismo , Ganglios Linfáticos/parasitología , Ratones Endogámicos C57BL , Análisis por Micromatrices , Vacunas Antiprotozoos/inmunología , Schistosoma mansoni/patogenicidad , Esquistosomiasis mansoni/inmunología , Esquistosomiasis mansoni/metabolismo , Esquistosomiasis mansoni/parasitología , Células TH1/inmunología , Células TH1/metabolismo , Células TH1/parasitología , Balance Th1 - Th2 , Células Th2/inmunología , Células Th2/metabolismo , Células Th2/parasitología , Factores de Tiempo , Transcriptoma , Vacunación , Vacunas Atenuadas/administración & dosificación , Vacunas Atenuadas/inmunologíaRESUMEN
A reliable and reproducible in vivo experimental model is an essential tool to study the pathogenesis of broiler necrotic enteritis and to evaluate control methods. Most current in vivo models use Eimeria as predisposing factor. Nevertheless, most models only result in a limited number of animals with intestinal necrosis. This research describes the necrotic enteritis incidence and severity using 2 previously described experimental models varying in the time point and frequency of Eimeria administration: single late and early repeated Eimeria administration models. In an in vivo model in which Clostridium perfringens is administered at 3 consecutive days between day 18 and 20 of age, birds belonging to the single late Eimeria administration regimen received a single administration of a tenfold dose of a live attenuated Eimeria vaccine on the second day of C. perfringens challenge. Broilers belonging to the early repeated administration regimen were inoculated with the same Eimeria vaccine 4 and 2 d before the start of the C. perfringens challenge. Early repeated coccidial administration resulted in a significant increase in average necrotic lesion score (value 3.26) as compared with a single late Eimeria administration regimen (value 1.2). In addition, the number of necrotic enteritis-positive animals was significantly higher in the group that received the early repeated coccidial administration. Single Eimeria administration during C. perfringens challenge resulted in a skewed distribution of lesion scoring with hardly any birds in the high score categories. A more centered distribution was obtained with the early repeated Eimeria administration regimen, having observations in every lesion score category. These findings allow better standardization of a subclinical necrotic enteritis model and reduction of the required numbers of experimental animals.
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Infecciones por Clostridium , Coccidiosis , Enteritis , Enfermedades de las Aves de Corral , Animales , Pollos , Infecciones por Clostridium/veterinaria , Clostridium perfringens , Coccidiosis/microbiología , Coccidiosis/parasitología , Coccidiosis/veterinaria , Modelos Animales de Enfermedad , Enteritis/microbiología , Enteritis/parasitología , Enteritis/veterinaria , Necrosis/microbiología , Necrosis/parasitología , Necrosis/veterinaria , Enfermedades de las Aves de Corral/microbiología , Enfermedades de las Aves de Corral/parasitología , Vacunas Antiprotozoos/administración & dosificación , Factores de TiempoRESUMEN
Control of human ascariasis, the most prevalent neglected tropical disease globally affecting 450 million people, mostly relies on mass drug administration of anthelmintics. However, chemotherapy alone is not efficient due to the high re-infection rate for people who live in the endemic area. The development of a vaccine that reduces the intensity of infection and maintains lower morbidity should be the primary target for infection control. Previously, our group demonstrated that immunization with crude Ascaris antigens in mice induced an IgG-mediated protective response with significant worm reduction. Here, we aimed to develop a multipeptide chimera vaccine based on conserved B-cell epitopes predicted from 17 common helminth proteomes using a bioinformatics algorithm. More than 480 B-cell epitopes were identified that are conserved in all 17 helminths. The Ascaris-specific epitopes were selected based on their reactivity to the pooled sera of mice immunized with Ascaris crude antigens or infected three times with A. suum infective eggs. The top 35 peptides with the strongest reactivity to Ascaris immune serum were selected to construct a chimeric antigen connected in sequence based on conformation. This chimera, called ASCVac-1, was produced as a soluble recombinant protein in an Escherichia coli expression system and, formulated with MPLA, was used to immunize mice. Mice immunized with ASCVac-1/MPLA showed around 50% reduced larvae production in the lungs after being challenged with A. suum infective eggs, along with significantly reduced inflammation and lung tissue/function damage. The reduced parasite count and pathology in infected lungs were associated with strong Th2 immune responses characterized by the high titers of antigen-specific IgG and its subclasses (IgG1, IgG2a, and IgG3) in the sera and significantly increased IL-4, IL-5, IL-13 levels in lung tissues. The reduced IL-33 titers and stimulated eosinophils were also observed in lung tissues and may also contribute to the ASCVac-1-induced protection. Taken together, the preclinical trial with ASCVac-1 chimera in a mouse model demonstrated its significant vaccine efficacy associated with strong IgG-based Th2 responses, without IgE induction, thus reducing the risk of an allergic response. All results suggest that the multiepitope-based ASCVac-1 chimera is a promising vaccine candidate against Ascaris sp. infections.
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Antígenos Helmínticos/administración & dosificación , Ascariasis/prevención & control , Ascaris suum/inmunología , Enfermedades Desatendidas/prevención & control , Vacunas Antiprotozoos/administración & dosificación , Animales , Antígenos Helmínticos/inmunología , Ascariasis/inmunología , Ascariasis/parasitología , Ascariasis/patología , Ascaris suum/aislamiento & purificación , Femenino , Humanos , Pulmón/inmunología , Pulmón/parasitología , Pulmón/patología , Ratones , Enfermedades Desatendidas/inmunología , Enfermedades Desatendidas/parasitología , Enfermedades Desatendidas/patología , Vacunas Antiprotozoos/inmunología , Células Th2/inmunología , Eficacia de las Vacunas , Vacunas de Subunidad/administración & dosificación , Vacunas de Subunidad/inmunologíaRESUMEN
The re-emerging disease histomonosis is caused by the protozoan parasite Histomonas meleagridis that affects chickens and turkeys. Previously, protection by vaccination with in vitro attenuated H. meleagridis has been demonstrated and an involvement of T cells, potentially by IFN-γ production, was hypothesized. However, comparative studies between chickens and turkeys on H. meleagridis-specific T cells were not conducted yet. This work investigated IFN-γ production within CD4+, CD8α+ and TCRγδ+ (chicken) or CD3ε+CD4-CD8α- (turkey) T cells of spleen and liver from vaccinated and/or infected birds using clonal cultures of a monoxenic H. meleagridis strain. In infected chickens, re-stimulated splenocytes showed a significant increase of IFN-γ+CD4+ T cells. Contrariwise, significant increments of IFN-γ-producing cells within all major T-cell subsets of the spleen and liver were found for vaccinated/infected turkeys. This indicates that the vaccine in turkeys causes more intense systemic immune responses whereas in chickens protection might be mainly driven by local immunity.
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Pollos/inmunología , Interferón gamma/inmunología , Vacunas Antiprotozoos/inmunología , Subgrupos de Linfocitos T/inmunología , Trichomonadida/inmunología , Pavos/inmunología , Animales , Pollos/parasitología , Hígado/inmunología , Enfermedades de las Aves de Corral/inmunología , Enfermedades de las Aves de Corral/parasitología , Enfermedades de las Aves de Corral/prevención & control , Infecciones Protozoarias en Animales/inmunología , Infecciones Protozoarias en Animales/parasitología , Infecciones Protozoarias en Animales/prevención & control , Vacunas Antiprotozoos/administración & dosificación , Bazo/inmunología , Pavos/parasitología , Vacunación/veterinariaRESUMEN
Unmethylated CpG motifs with phosphothioate backbone trigger TLR9 to elicit innate immune response characterized by the production of Th1 cytokines. The use of CpG DNA as an adjuvant has established its role in potentiating the humoral and cell mediated vaccine specific immune response. However, none of the synthetic oligodeoxynucleotides (ODNs) know and used till date are associated with the parasite itself. Our group identified a novel CG rich sequence of 14 base pairs from Leishmania donovani genome (Ld CpG ODN) and established it as a TLR9 agonist. The present study was designed to ascertain the adjuvanticity of Ld CpG ODN with soluble leishmanial antigen in experimental model of L. donovani. During the study Schizophyllan (SPG), a fungal polymer was used for encapsulating Ld CpG ODN for efficient endosomal delivery. The synthesized nanovehicles were of nearly 100 nm and localized within endosomes as confirmed by confocal microscopy. Immunization studies displayed the superior ability of synthesized nanovehicles co-administered with parasite antigen in augmenting innate immune response in comparison to ODN, nanoparticles or soluble antigen alone. The response included generation of ROS, NO and iNOS expression followed by proinflammatory cytokine milieu with reduced parasitic load within liver, spleen and bone marrow. These immune-tailored particles in combination with parasitic antigens elicited significant generation of cell mediated response owing to the presence of high levels of CD8+ T-cells and lymphocyte proliferation. Moreover, vaccination regime with synthesized adjuvant also activated humoral immunity by escalating the levels of IgG2 followed by reduced levels of anti-leishmanial IgG and IgG1 antibodies. The findings support the efficacy of Ld CpG ODN as a potential adjuvant against visceral leishmaniasis.