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1.
Exp Parasitol ; 223: 108082, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33581108

RESUMEN

Leishmaniasis is a complex vector-borne disease mediated by Leishmania parasite and a strong and long-lasting CD4+ Th1 and CD8+-T cell immunity is required to control the infection. Thus far multivalent subunit vaccines have met this requirement more promisingly. However several full protein sequences cannot be easily arranged in one construct. Instead, new emerging immune-informatics based epitope formulations surpass this restriction. Herein, we aimed to examine the protective potential of a dendritic cell based vaccine presenting epitopes to CD8+ and CD4+-T cells in combination with DNA vaccine encoding the same epitopes against murine cutaneous leishmaniasis. Immature DCs were loaded with epitopes (selected from parasite proteome) in vitro with or without CpG oligonucleotides and were used to immunize BALB/c mice. Peptide coding DNA was used to boost the system and immunological responses were evaluated after Leishmania (L.) major infectious challenge. The pre-challenge response to included epitopes was Th1 polarized which potentially lowered the infection at early time points post-challenge but not at later weeks. Collectively, DC prime-DNA boost was found to be a promising approach for Th1 polarization however the constituent epitopes undoubtedly make a significant contribution in the protection outcome of the vaccine.


Asunto(s)
Células de la Médula Ósea/inmunología , Linfocitos T CD8-positivos/inmunología , Células Dendríticas/inmunología , Leishmania major/inmunología , Leishmaniasis Cutánea/prevención & control , Vacunas Antiprotozoos , Secuencia de Aminoácidos , Animales , Linfocitos T CD4-Positivos/inmunología , Citocinas/metabolismo , Epítopos/química , Epítopos/inmunología , Femenino , Ratones , Ratones Endogámicos BALB C , Óxido Nítrico/metabolismo , Proteoma/química , Vacunas de ADN
2.
Vet Res ; 52(1): 29, 2021 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-33602319

RESUMEN

Rhomboid-like proteases (ROMs) are considered as new candidate antigens for developing new-generation vaccines due to their important role involved in the invasion of apicomplexan protozoa. In prior works, we obtained a ROM2 sequence of Eimeria maxima (EmROM2). This study was conducted to evaluate the immunogenicity and protective efficacy of EmROM2 recombinant protein (rEmROM2) and EmROM2 DNA (pVAX1-EmROM2) against infection by Eimeria maxima (E. maxima). Firstly, Western blot assay was conducted to analyze the immunogenicity of rEmROM2. The result showed that rEmROM2 was recognized by chicken anti-E. maxima serum. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot assay revealed apparent transcription and expression of EmROM2 at the injection site. qRT-PCR (quantitative real-time PCR), flow cytometry and indirect ELISA indicated that vaccination with rEmROM2 or EmROM2 DNA significantly upregulated the transcription level of cytokines (IFN-γ, IL-2, IL-4, IL-10, IL-17, TGF-ß and TNF SF15), the proportion of CD8+ and CD4+ T lymphocytes and serum IgG antibody response. Ultimately, a vaccination-challenge trial was performed to evaluate the protective efficacy of rEmROM2 and pVAX1-EmROM2 against E. maxima. The result revealed that vaccination with rEmROM2 or pVAX1-EmROM2 significantly alleviated enteric lesions, weight loss, and reduced oocyst output caused by challenge infection of E. maxima, and provided anticoccidial index (ACI) of more than 160, indicating partial protection against E. maxima. In summary, vaccination with rEmROM2 or pVAX1-EmROM2 activated notable humoral and cell-mediated immunity and provided partial protection against E. maxima. These results demonstrated that EmROM2 protein and DNA are promising vaccine candidates against E. maxima infection.


Asunto(s)
Coccidiosis/prevención & control , Eimeria/metabolismo , Péptido Hidrolasas/metabolismo , Proteínas Protozoarias/metabolismo , Vacunas Antiprotozoos/inmunología , Animales , Pollos , Clonación Molecular , Eimeria/genética , Regulación de la Expresión Génica , Inmunización Secundaria , Inmunoglobulina G/sangre , Péptido Hidrolasas/genética , Proteínas Protozoarias/genética , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes
3.
Trends Parasitol ; 37(2): 165-175, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33502317

RESUMEN

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis, an infection that manifests as colitis and, in some cases, liver abscess. A better understanding of host protective factors is key to developing an effective remedy. Recently, significant advances have been made in understanding the mechanisms of MUC2 production by goblet cells upon amebic infection, regulation of antimicrobial peptide production by Paneth cells, the interaction of commensal microbiota with immune stimulation, and host genetics in conferring protection from amebiasis. In addition to host pathways that may serve as potential therapeutic targets, significant progress has also been made with respect to development of a vaccine against amebiasis. Here, we aim to highlight the current understanding and knowledge gaps critically.


Asunto(s)
Entamebiasis/inmunología , Interacciones Huésped-Parásitos/inmunología , Entamoeba histolytica , Entamebiasis/genética , Entamebiasis/parasitología , Entamebiasis/prevención & control , Células Caliciformes/inmunología , Células Caliciformes/parasitología , Humanos , Mucina 2/inmunología , Células de Paneth/inmunología , Proteínas Citotóxicas Formadoras de Poros/inmunología , Vacunas Antiprotozoos
4.
Methods Mol Biol ; 2183: 331-356, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32959252

RESUMEN

Vaccination was developed by Edward Jenner in 1796. Since then, vaccination and vaccine development research has been a hotspot of research in the scientific community. Various ways of vaccine development are successfully employed in mass production of vaccines. One of the most successful ways to generate vaccines is the method of virulence attenuation in pathogens. The attenuated strains of viruses, bacteria, and parasites are used as vaccines which elicit robust immune response and confers protection against virulent pathogens. This chapter brings together the most common and efficient ways of generating live attenuated vaccine strains in viruses, bacteria, and parasites.


Asunto(s)
Vacunas Atenuadas/inmunología , Vacunología/métodos , Animales , Vacunas Bacterianas , Línea Celular , Uso de Codones , Femenino , Rayos gamma , Silenciador del Gen , Humanos , Inmunización , Inmunogenicidad Vacunal , Virus de la Influenza A , Ratones , MicroARNs/genética , Modelos Animales , Mutagénesis , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Vacunas Antiprotozoos/genética , Vacunas Antiprotozoos/inmunología , Radiación Ionizante , Vacunas Atenuadas/genética , Virulencia/inmunología
5.
Mem Inst Oswaldo Cruz ; 115: e200067, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32667458

RESUMEN

BACKGROUND Unfortunately, no any vaccine against leishmaniasis has been developed for human use. Therefore, a vaccine based on total Leishmania antigens could be a good and economic approach; and there are different methodologies to obtain these antigens. However, it is unknown whether the method to obtain the antigens affects the integrity and immune response caused by them. OBJECTIVES to compare the protein profile and immune response generated by total L. amazonensis antigens (TLA) produced by different methods, as well as to analyse the immune response and protection by a first-generation vaccine formulated with sonicated TLA (sTLA) and polyinosinic:polycytidylic acid [Poly (I:C)]. METHODS TLA were obtained by four different methodologies and their integrity and immune response were evaluated. Finally, sTLA was formulated with Poly (I:C) and their protective immune response was measured. FINDINGS sTLA presented a conserved protein profile and induced a strong immune response. In addition, Poly (I:C) improved the immune response generated by sTLA. Finally, sTLA + Poly (I:C) formulation provided partial protection against L. amazonensis infection. MAIN CONCLUSIONS The protein profile and immune response depend on the methodology used to obtain the antigens. Also, the formulation sTLA + Poly (I:C) provides partial protection against cutaneous leishmaniasis in mice.


Asunto(s)
Leishmania , Vacunas contra la Leishmaniasis , Leishmaniasis Cutánea/inmunología , Leishmaniasis Cutánea/prevención & control , Vacunas Antiprotozoos/inmunología , Receptor Toll-Like 3/inmunología , Animales , Antígenos de Protozoos/inmunología , Humanos , Ratones , Ratones Endogámicos BALB C
6.
Parasitol Res ; 119(9): 2885-2895, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32715344

RESUMEN

Chicken coccidiosis is a protozoan parasitic disease that leads to considerable economic losses in the poultry industry. In this study, we used invasive Lactobacillus plantarum (L.P) expressing the FnBPA protein as a novel bacterial carrier for DNA delivery into epithelial cells to develop a live oral DNA vaccine. A fusion DNA vaccine co-expressing EtMIC2 and chicken IL-18 (chIL-18) was constructed and then delivered to the host by invasive L.P. Its efficacy against Eimeria tenella challenge was evaluated in chickens by examining the relative weight gain rate; caecal lesion score; OPG; anti-coccidial index (ACI); levels of EtMIC2 antibody, FnBPA, IL-4, IL-18, IFN-γ and SIgA; and proliferation ability and percentages of CD4+ and CD8+ splenocytes. The experimental results showed that chickens immunized with invasive L.P carrying the eukaryotic expression vector pValac-EtMIC2 (pValac-EtMIC2/pSIP409-FnBPA) had markedly improved immune protection against challenge compared with that of chickens immunized with non-invasive L.P (pValac-EtMIC2/pSIP409). However, invasive L.P co-expressing EtMIC2 with the chIL-18 vector exhibited the highest protection efficiency against E. tenella. These results indicate that invasive Lactobacillus-expressing FnBPA improved humoural and cellular immunity and enhanced resistance to E. tenella. The DNA vaccine delivered by invasive Lactobacillus provides a new concept and method for the prevention of E. tenella.


Asunto(s)
Antígeno 12E7/metabolismo , Coccidiosis/veterinaria , Eimeria tenella/inmunología , Interleucina-18/metabolismo , Lactobacillus plantarum/metabolismo , Vacunas Antiprotozoos/inmunología , Vacunas de ADN/inmunología , Animales , Ciego/parasitología , Pollos/parasitología , Coccidiosis/parasitología , Eimeria tenella/genética , Inmunidad Celular/inmunología , Inmunoglobulina A Secretora/genética , Lactobacillus plantarum/genética , Enfermedades de las Aves de Corral/parasitología , Enfermedades de las Aves de Corral/prevención & control , Vacunación/veterinaria , Aumento de Peso
7.
BMC Infect Dis ; 20(1): 493, 2020 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-32650739

RESUMEN

BACKGROUND: Toxoplasma gondii is an obligate intracellular parasite that can infect almost all warm-blooded animals, avian species and humans. Toxoplasmosis is asymptomatic in healthy individuals, whereas it may lead to death in immune suppressed or deficient patients. A vaccine against T. gondii is required to prevent consequences of the infection. The aim of this study is to generate a multivalent recombinant protein vaccine against T. gondii. METHODS: 49 previously discovered antigenic proteins of T gondii were evaluated by their expression level in E. coli and by comprehensive bioinformatics analyses to determine antigenic epitopes. Based on these analyses, six vaccine candidate proteins were selected to generate a hexavalent recombinant protein vaccine adjuvanted with Montanide ISA 50 V. Humoral and cellular immune responses were determined by flow cytometry and ELISA. Vaccinated mice were challenged with T. gondii Ankara strain tachyzoites. RESULTS: In mice vaccinated with hexavalent vaccine, strong total IgG (P < 0.0001) and IgG2a (P < 0.001) responses were induced compared to controls, the ratio of CD4+ and CD8+ T lymphocytes secreting IFN-γ increased, and significantly higher extracellular IFN-γ secretion was achieved compared to the controls (P < 0.001). The survival time of the vaccinated mice increased to 8.38 ± 2.13 days which was significantly higher than controls (P < 0.01). CONCLUSIONS: Altogether, these results show that the hexavalent vaccine which is developed for the first time against T. gondii induced strong and balanced Th1 and Th2 immune responses as well as conferred significant protection against challenge with lethal toxoplasmosis in murine model.


Asunto(s)
Adyuvantes Inmunológicos/farmacología , Manitol/análogos & derivados , Vacunas Antiprotozoos/farmacología , Toxoplasmosis/prevención & control , Vacunas de ADN/farmacología , Animales , Ensayo de Inmunoadsorción Enzimática , Epítopos/genética , Epítopos/inmunología , Escherichia coli/genética , Femenino , Inmunidad Celular/efectos de los fármacos , Inmunidad Humoral/efectos de los fármacos , Inmunoglobulina G/sangre , Manitol/farmacología , Ratones , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos/genética , Vacunas Antiprotozoos/inmunología , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Toxoplasma/patogenicidad , Toxoplasmosis/inmunología , Vacunas de ADN/inmunología
8.
Exp Parasitol ; 216: 107944, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32619431

RESUMEN

Evaluation of the murine isotype antibodies is essential in subunit vaccine development because inbred mouse strains with diverse genetic backgrounds respond different to recombinant proteins. In this regard, the main goal of this study was to measuring and comparing the profile of IgG isotype responses in C57BL/6 mice. For this purpose, the extracellular region of plasmodium vivax thrombospondin-related adhesive protein (PvTRAP) gene was expressed in Escherichia coli Rosetta (DE3)-pET23a. Then, the recombinant PvTRAP alone or emulsified with Freund's complete adjuvant were applied for immunization of the C57BL/6 mice. The role of antibodies and cellular immune responses induced by recombinant PvTRAP were evaluated. The results showed the level of anti-rPvTRAP IgG2c was significantly higher than IgG2a in the groups that received rPvTRAP alone (mean OD490 = 0.798 ± 0.12 and 0.39 ± 0.1, respectively) and emulsified with CFA/IFA (mean OD490 = 1.48 ± 0.07 and 0.605 ± 0.13, respectively; P < 0.05, independent sample t-test). Additionally, the immunized mice with rPvTRAP and rPvTRAP + CFA/IFA had an intermediate-avidity IgG2a antibody but high-avidity IgG2c antibody as well as the mean of serum antibody titers results exhibited that in both rPvTRAP and rPvTRAP + CFA/IFA mouse groups, IgG2a end-point titer (1:3200 and 1:25,600, respectively) was noteworthy lower than IgG2c (1:25,600 and 1:102,400, respectively). Moreover, the results revealed the eliciting significant levels of IFN-γ (P < 0.05, independent sample t-test) and no detectable level of IL-4 in the mouse groups received rPvTRAP alone and emulsified with CFA/IFA as compared to the mouse control groups. In general, our results showed that for correctly interpreting of Th1 immune responses in C57BL/6 mouse strain it is critical to measure IgG2c instead of IgG2a along with IFN-γ.


Asunto(s)
Inmunoglobulina G/sangre , Plasmodium vivax/inmunología , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos/inmunología , Células TH1/inmunología , Células Th2/inmunología , Animales , Afinidad de Anticuerpos , Dicroismo Circular , Femenino , Técnica del Anticuerpo Fluorescente , Inmunoglobulina G/clasificación , Interferón gamma/análisis , Interleucina-4/análisis , Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Proteínas Recombinantes/inmunología , Vacunas de Subunidad/inmunología , Vacunas Sintéticas/inmunología
9.
Exp Parasitol ; 216: 107945, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32615133

RESUMEN

Despite decades of investigation to clarify protective mechanisms of anticoccidial responses, one crucial field is neglected, that is, protective memory responses in primed birds. Protective memory immunity is critical for host resistance to reinfection and is the basis of modern vaccinology, especially in developing successful subunit vaccines. There are important differences between the immune responses induced by infections and antigens delivered either as killed, recombinant proteins or as live, replicating vector vaccines or as DNA vaccines. Animals immunized with these vaccines may fail to develop protective memory immunity, and is still naïve to Eimeria infection. This may explain why limited success is achieved in developing next-generation anticoccidial vaccines. In this review, we try to decipher the protective memory responses against Eimeria infection, assess immune responses elicited by various anticoccidial vaccine candidates, and propose possible approaches to develop rational vaccines that can induce a protective memory response to chicken coccidiosis.


Asunto(s)
Pollos/parasitología , Coccidiosis/veterinaria , Eimeria/inmunología , Memoria Inmunológica/fisiología , Enfermedades de las Aves de Corral/inmunología , Vacunas Antiprotozoos , Animales , Pollos/inmunología , Coccidiosis/inmunología , Coccidiosis/prevención & control , Intestinos/inmunología , Intestinos/parasitología , Enfermedades de las Aves de Corral/prevención & control , Vacunas Antiprotozoos/inmunología , Recurrencia , Vacunación/veterinaria , Vacunas de Subunidad/inmunología
10.
Exp Parasitol ; 215: 107901, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32525007

RESUMEN

Eimeria tenella (E. tenella) has caused severe economic loss in chicken production, especially after the forbidden use of antibiotics in feed. Considering the drug resistant problem caused by misuse of chemoprophylaxis and live oocyst vaccines can affect the productivity of chickens, also it has the risk to reversion of virulence, the development of efficacious, convenient and safe vaccines is still deeply needed. In this study, the EtMic2 protein of E. tenella was anchored on the surface of Lactobacillus plantarum (L. plantarum) NC8 strain. The newly constructed strain was then used to immunize chickens, followed by E. tenella challenge. The results demonstrated that the recombinant strain could provide efficient protection against E. tenella, shown by increased relative body weight gains, percentages of CD4+ and CD8+ T cells, humoral immune response and inflammatory cytokines. In addition, decreased cecum lesion scores and fecal oocyst shedding were also observed during the experiment. In conclusion, this study proves the possibility to use L. plantarum as a vessel to deliver protective antigen to protect chickens against coccidiosis.


Asunto(s)
Antígeno 12E7/inmunología , Pollos/parasitología , Coccidiosis/veterinaria , Eimeria tenella/inmunología , Enfermedades de las Aves de Corral/prevención & control , Vacunas Antiprotozoos , Animales , Antígenos de Protozoos/inmunología , Ciego/parasitología , Coccidiosis/economía , Coccidiosis/parasitología , Coccidiosis/prevención & control , Eimeria tenella/química , Citometría de Flujo/veterinaria , Técnica del Anticuerpo Fluorescente Indirecta/veterinaria , Inmunoglobulina A Secretora/biosíntesis , Inmunoglobulina G/sangre , Interferón gamma/sangre , Interleucina-2/sangre , Intestinos/inmunología , Lactobacillus plantarum/genética , Lactobacillus plantarum/inmunología , Enfermedades de las Aves de Corral/economía , Enfermedades de las Aves de Corral/parasitología , Distribución Aleatoria , Vacunas Sintéticas
11.
PLoS Negl Trop Dis ; 14(6): e0008358, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32589656

RESUMEN

Antibody-mediated parasite killing is considered the most effective host immune response against extracellular trypanosome parasites. However, due to host-parasite co-evolution pressure, these parasites have "learned" how to hijack the host immune system via the development of immune evasion strategies. Hereby they prevent elimination and promote transmission. In the past, our group has shown that African trypanosome parasites are able to "shut down" the host B cell compartment, via the abolishment of the homeostatic B cell compartment. In line with this, we have reported that trypanosome infections result in detrimental outcomes on auto-reactive and cancer B cells. To unravel the immune mechanisms involved in these processes we adopted here a well-defined B cell vaccine model, i.e. the thymo-dependent hapten-carrier NP-CGG (4-Hydroxy-3-nitrophenylacetyl-Chicken Gamma Globulin) emulsified in Alum adjuvant. Results show that T. brucei infections abrogate the circulating titres of vaccine-induced CGG-specific as well as NP-specific IgG1+ antibodies, a hallmark of memory B cell responses in this model. This happens independently of their affinity and IFNÉ£ signalling. Next, we demonstrate that T. brucei infections also induce a decrease of anti-NP IgG3+ antibodies induced by the administration of NP coupled to Ficoll, a thymo-independent antigen. Confirming the non-specificity of the infection-associated immunopathology, this report also shows that trypanosome infections abolish vaccine-induced memory response against malaria parasite in BALB/c mice. Together, these data indicates that T. brucei infections impair every stages of B cell development, including effector plasma B cells, independently of their specificity and affinity as well as the host genetic background.


Asunto(s)
Subgrupos de Linfocitos B/inmunología , Células Plasmáticas/inmunología , Tripanosomiasis Africana/inmunología , Animales , Anticuerpos Antiprotozoarios/inmunología , Antígenos de Protozoos/inmunología , Linfocitos B/inmunología , Modelos Animales de Enfermedad , Femenino , Antecedentes Genéticos , Interacciones Huésped-Parásitos/inmunología , Evasión Inmune , Inmunidad Humoral , Inmunoglobulina G , Activación de Linfocitos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Vacunas Antiprotozoos/inmunología , Trypanosoma brucei brucei
12.
PLoS Negl Trop Dis ; 14(4): e0007717, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32302312

RESUMEN

BACKGROUND: The long term and complex nature of Chagas disease in humans has restricted studies on vaccine feasibility. Animal models also have limitations due to technical difficulties in monitoring the extremely low parasite burden that is characteristic of chronic stage infections. Advances in imaging technology offer alternative approaches that circumvent these problems. Here, we describe the use of highly sensitive whole body in vivo imaging to assess the efficacy of recombinant viral vector vaccines and benznidazole-cured infections to protect mice from challenge with Trypanosoma cruzi. METHODOLOGY/PRINCIPAL FINDINGS: Mice were infected with T. cruzi strains modified to express a red-shifted luciferase reporter. Using bioluminescence imaging, we assessed the degree of immunity to re-infection conferred after benznidazole-cure. Those infected for 14 days or more, prior to the onset of benznidazole treatment, were highly protected from challenge with both homologous and heterologous strains. There was a >99% reduction in parasite burden, with parasites frequently undetectable after homologous challenge. This level of protection was considerably greater than that achieved with recombinant vaccines. It was also independent of the route of infection or size of the challenge inoculum, and was long-lasting, with no significant diminution in immunity after almost a year. When the primary infection was benznidazole-treated after 4 days (before completion of the first cycle of intracellular infection), the degree of protection was much reduced, an outcome associated with a minimal T. cruzi-specific IFN-γ+ T cell response. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that a protective Chagas disease vaccine must have the ability to eliminate parasites before they reach organs/tissues, such as the GI tract, where once established, they become largely refractory to the induced immune response.


Asunto(s)
Enfermedad de Chagas/inmunología , Enfermedad de Chagas/prevención & control , Inmunidad Heteróloga , Vacunas Antiprotozoos/inmunología , Trypanosoma cruzi/inmunología , Vacunación/métodos , Animales , Modelos Animales de Enfermedad , Femenino , Ratones Endogámicos BALB C , Vacunas Antiprotozoos/administración & dosificación , Vacunas de Subunidad/administración & dosificación , Vacunas de Subunidad/inmunología , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/inmunología
13.
Br Poult Sci ; 61(5): 518-522, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32347110

RESUMEN

1. Immune mapped protein-1 (IMP1) of E. maxima has been identified as a vaccine antigen candidate for E. maxima infection. 2. In the current study, the N- and C-terminal derivative of EmIMP1 were expressed in E. coli and administered to chickens. The antibody response, cell-mediated immune (CMI) response and the protective efficacy of the protein vaccines against E. maxima challenge were evaluated. 3. The results showed that C-terminal derivative of EmIMP1 vaccination could increase weight gain, reduce enteric lesions, and decrease faecal oocysts shedding. Moreover, the C-terminal derivative of EmIMP1 caused reasonable improvement in serum antibodies and the numbers of IFN-γ producing peripheral blood mononuclear cells (PBMC), as compared to the control group. 4. This study demonstrated that the C-terminal derivative of EmIMP1 could be used as a potent immunogenic candidate in the development of subunit vaccines against E. maxima infection.


Asunto(s)
Coccidiosis , Eimeria , Enfermedades de las Aves de Corral , Vacunas Antiprotozoos , Animales , Antígenos de Protozoos , Pollos , Coccidiosis/veterinaria , Escherichia coli , Leucocitos Mononucleares , Enfermedades de las Aves de Corral/prevención & control
14.
Vet Parasitol ; 279: 109061, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32143014

RESUMEN

The microneme adhesive repeats (MAR) of Eimeria tenella microneme protein 3 (EtMIC3) are associated with binding to and invasion of host cells. Adhesion and invasion-related proteins or domains are often strongly immunogenic, immune responses mounted against these factors that play a key role in blocking invasion. In the present study, an oral live vaccine consisting of attenuated Salmonella typhimurium X4550 carrying two MAR domains fragment (St-X4550-MAR) was constructed and its protective efficacies were evaluated. The results showed that St-X4550-MAR was more immunogenic and conferred a higher degree of protection than recombinant MAR polypeptide as reflected by increased body weight, decreased oocyst shedding and lesion scores, increased serum IgG and cecal sIgA antibody production, and increasing levels of interferon-γ and interleukin-10. Thus, MAR domains are highly immunogenic and St-X4550-MAR had moderate activity against E. tenella infection by stimulating humoral, mucosal and cellular immunity. Chickens immunized with our constructed live vaccine provided considerable protections as early as at 10 d post-immunization (ACI: 155.17), and maintained higher protection levels at 20 d post-immunization (ACI: 173.66), and at 30 d post-immunization (ACI: 162.4). While the protective efficacy of chickens immunized with the recombinant MAR peptides showed a decreased trend as the post immunization time prolonging. Thus, using live-attenuated S. typhimurium X4550 as a vaccine expression and delivery system can significantly improve the protective efficacy and duration of protective immunity of MAR of EtMIC3.


Asunto(s)
Pollos , Coccidiosis/veterinaria , Eimeria tenella/inmunología , Inmunización/veterinaria , Enfermedades de las Aves de Corral/prevención & control , Vacunas Antiprotozoos/inmunología , Animales , Coccidiosis/parasitología , Coccidiosis/prevención & control , Masculino , Microorganismos Modificados Genéticamente , Enfermedades de las Aves de Corral/parasitología , Salmonella typhimurium , Vacunas Atenuadas/inmunología , Vacunas Sintéticas/inmunología
15.
Parasitol Res ; 119(5): 1619-1628, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32185481

RESUMEN

Schistosomiasis is still prevalent and seriously endangering the health of people and livestock in many countries. There have been great efforts to develop vaccines against schistosomiasis for prolonged protection in epidemic areas. Molecules from lung-stage schistosomula have been regarded as potential vaccine candidates against schistosomiasis. Our previous work has shown that cathepsin L3 from Schistosoma japonicum (SjCL3) is expressed in lung-stage schistosomula, but its role is not well known. In the present study, we characterized SjCL3 and detected its effect as a possible vaccine in vivo and in vitro. From the results of quantitative PCR (qPCR) and western blot, SjCL3 was present throughout the lifecycle of the worm, and its relative expressed level was higher in the liver eggs and adult worms than other stages. Additionally, immunofluorescence assay showed that SjCL3 was mainly concentrated in the eggshell, alimentary canal, and musculature of worms. Compared with the adjuvant group, the immunization of SjCL3 in mice resulted in a 28.9% decrease in worm burden and a 29.2% reduction in egg number in the host liver. In antibody-dependent cell-mediated cytotoxicity (ADCC) insecticidal experiments in vitro, the existence of SjCL3 could in part suppress adherence between macrophages and worm. The above results indicated that the immunization of SjCL3 could induce limited immune protection against S. japonicum infection in mice, and this protease played a role in breaking the process of ADCC, which was beneficial to the survival of worms.


Asunto(s)
Catepsinas/inmunología , Vacunas Antiprotozoos/inmunología , Schistosoma japonicum/inmunología , Esquistosomiasis Japónica/prevención & control , Adyuvantes Inmunológicos , Animales , Citotoxicidad Celular Dependiente de Anticuerpos/inmunología , Western Blotting , Clonación Molecular , Femenino , Macrófagos/inmunología , Ratones , Ratones Endogámicos BALB C , Schistosoma japonicum/metabolismo , Esquistosomiasis Japónica/inmunología , Vacunación
16.
Transbound Emerg Dis ; 67 Suppl 1: 79-87, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32174035

RESUMEN

The infection and treatment (ITM) procedure remains the only available method of immunization against Theileria parva infection. One constraint to deployment is the perception that the carrier state induced by ITM could result in enhanced disease problems. More than one million cattle have been ITM vaccinated in pastoralist systems in Tanzania over the last 2 decades. We present the results of a longitudinal study of six groups of cattle in Maasai villages in northern Tanzania exposed to natural tick challenge for between 2 weeks and 14 years post-vaccination. The p104 nested PCR revealed a higher frequency of T. parva carriers among vaccinates (30%) compared with controls (8%) (OR = 4.89, p = .000), with the highest frequency of carriers found in calves vaccinated 6 months previously, although carrier state was also detected in cattle vaccinated >10 years prior to the study. Variable number tandem repeat genotype analysis revealed 6 MS7 alleles with sizes ranging from 150 bp to 500 bp, but only two alleles were detected in cattle vaccinated >4 years earlier, relative to five alleles detected in recently vaccinated cattle and controls. In terms of heterozygosity, diversity was maximal in calves vaccinated within the last 2 weeks (h = 0.776) but lowest in cattle vaccinated 4 years earlier (h = 0.375). The analysis suggested close genetic relatedness of parasites in vaccinated and unvaccinated groups and up to 96% of variation was within rather than between the groups. These results confirm that ITM leads to a long-term T. parva carrier state in cattle and the detection of vaccine component VNTR in co-grazing unvaccinated cattle suggests potential vaccine transmission by ticks. However, vaccination stocks did not totally replace local genotypes, at least in cattle populations. These findings should mitigate concerns that ITM modifies T. parva field populations in a way that enhances disease in the medium term.


Asunto(s)
Vectores Arácnidos/parasitología , Enfermedades de los Bovinos/prevención & control , Vacunas Antiprotozoos/inmunología , Theileria parva/inmunología , Theileriosis/prevención & control , Garrapatas/parasitología , Vacunación/veterinaria , Animales , Portador Sano , Bovinos , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/transmisión , Monitoreo Epidemiológico , Variación Genética , Genotipo , Estudios Longitudinales , Reacción en Cadena de la Polimerasa/veterinaria , Tanzanía/epidemiología , Theileriosis/parasitología , Theileriosis/transmisión , Vacunas Atenuadas/inmunología
17.
Transbound Emerg Dis ; 67 Suppl 1: 8-25, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32174036

RESUMEN

Tropical theileriosis caused by the apicomplexan hemoparasite Theileria annulata is a tick-borne disease that constraints livestock production in parts of Europe, Asia and Africa. Four Hyalomma tick species transmit T. annulata in at least eight Africa countries (Mauritania, Morocco, Algeria, Tunisia, Egypt, Sudan, South Sudan and Ethiopia). The two dominant T. annulata vector ticks present in Africa, H. scupense and H. anatolicum, underlie two different patterns of transmission, which in turn greatly influence the epidemiology of tropical theileriosis. H. dromedarii and H. lusitanicum are also capable of transmitting T. annulata in North Africa, but their roles are associated with specific production systems and agro-ecological contexts. The emergence of resistance to the most widely used theilericidal compound, buparvaquone, continues to limit the effectiveness of chemotherapy. In addition, acaricide use is increasingly becoming unsustainable. Deployable T. annulata attenuated live vaccines established from local strains in Tunisia, Sudan and Egypt are available, and recent work has indicated that these vaccines can be protective under conditions of natural transmission. However, vaccination programmes may vary over space and time due to differences in the prevalence of disease amongst cattle populations, as well seasonal variation in vector activity. We review recent descriptive and analytical surveys on the epidemiology of T. annulata infection with reference to (a) demographic aspects such as breeds and ages of cattle herds previously exposed to distinct T. annulata infection pressures and (b) seasonal dynamics of tick activity and disease transmission. We then discuss how the wider endemic patterns that we delineate can underpin the development and execution of future vaccination programmes. We also outline options for integrated control measures targeting tick vectors and husbandry practices.


Asunto(s)
Vectores Arácnidos/parasitología , Vacunas Antiprotozoos/inmunología , Theileria annulata/inmunología , Theileriosis/epidemiología , Enfermedades por Picaduras de Garrapatas/veterinaria , Garrapatas/parasitología , Vacunación/veterinaria , África del Norte/epidemiología , Animales , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/prevención & control , Prevalencia , Estaciones del Año , Theileriosis/parasitología , Theileriosis/prevención & control , Enfermedades por Picaduras de Garrapatas/epidemiología , Enfermedades por Picaduras de Garrapatas/parasitología , Enfermedades por Picaduras de Garrapatas/prevención & control , Vacunas Atenuadas/inmunología
18.
Transbound Emerg Dis ; 67 Suppl 1: 26-34, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32174037

RESUMEN

Tropical theileriosis constraints the development of the dairy industry in the Sudan and vaccination using live attenuated schizont vaccines is considered a promising measure for its control. The present study was carried out to investigate the ability of recombinant T. annulata surface protein (TaSP) to improve the efficacy of the attenuated Atbara cell line in protecting calves against field challenge. To this end, 23 cross-bred (Friesian × Kenana) calves were divided into four groups. Animals in group 1 (n = 5) were left unvaccinated. Group 2 (n = 6) received the Atbara cell line, animals in group 3 (n = 6) were immunized with three doses of TaSP on days 21, 49 and 77, while animals in group 4 (n = 6) received the cell line vaccine on day 0 and three doses of TaSP in Freund's incomplete adjuvant at days 21, 49 and 77. Twenty-eight days after the last TaSP boost, all groups were challenged by exposing them to natural field tick infestation in a region known to be endemic for tropical theileriosis. No thermal reactions, piroplasms or schizonts were observed in the immunized animals following immunization. Upon challenge, all animals showed a range of symptoms of clinical theileriosis with variable degrees of severity. The application of TaSP alone appeared to have no effect in terms of protection. The efficacy of the cell line alone was lower than the 100% level of protection against mortality observed in the group that received the combined cell line vaccine and TaSP, suggesting a synergistic effect of this combination.


Asunto(s)
Enfermedades de los Bovinos/prevención & control , Inmunización/veterinaria , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos/inmunología , Theileria annulata/inmunología , Theileriosis/prevención & control , Enfermedades por Picaduras de Garrapatas/veterinaria , Animales , Bovinos , Enfermedades de los Bovinos/parasitología , Línea Celular , Esquizontes , Esporozoítos , Theileriosis/parasitología , Enfermedades por Picaduras de Garrapatas/parasitología , Vacunas Atenuadas/inmunología , Vacunas de Subunidad/inmunología
19.
Transbound Emerg Dis ; 67 Suppl 1: 99-107, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32174038

RESUMEN

Theileria parva is a tick-transmitted apicomplexan protozoan parasite that infects lymphocytes of cattle and African Cape buffalo (Syncerus caffer), causing a frequently fatal disease of cattle in eastern, central and southern Africa. A live vaccination procedure, known as infection and treatment method (ITM), the most frequently used version of which comprises the Muguga, Serengeti-transformed and Kiambu 5 stocks of T. parva, delivered as a trivalent cocktail, is generally effective. However, it does not always induce 100% protection against heterologous parasite challenge. Knowledge of the genetic diversity of T. parva in target cattle populations is therefore important prior to extensive vaccine deployment. This study investigated the extent of genetic diversity within T. parva field isolates derived from Ankole (Bos taurus) cattle in south-western Uganda using 14 variable number tandem repeat (VNTR) satellite loci and the sequences of two antigen-encoding genes that are targets of CD8+T-cell responses induced by ITM, designated Tp1 and Tp2. The findings revealed a T. parva prevalence of 51% confirming endemicity of the parasite in south-western Uganda. Cattle-derived T. parva VNTR genotypes revealed a high degree of polymorphism. However, all of the T. parva Tp1 and Tp2 alleles identified in this study have been reported previously, indicating that they are widespread geographically in East Africa and highly conserved.


Asunto(s)
Antígenos de Protozoos/genética , Búfalos/parasitología , Enfermedades de los Bovinos/parasitología , Repeticiones de Minisatélite/genética , Vacunas Antiprotozoos/inmunología , Theileria parva/genética , Theileriosis/parasitología , Alelos , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/parasitología , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/prevención & control , Femenino , Variación Genética , Genotipo , Masculino , Polimorfismo Genético/genética , Theileria parva/inmunología , Theileriosis/epidemiología , Theileriosis/prevención & control , Garrapatas/parasitología , Uganda/epidemiología , Vacunas Atenuadas/inmunología
20.
Transbound Emerg Dis ; 67 Suppl 1: 56-67, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32174044

RESUMEN

The infection and treatment (ITM) live vaccination method for control of Theileria parva infection in cattle is increasingly being adopted, particularly in Maasai pastoralist systems. Several studies indicate positive impacts on human livelihoods. Importantly, the first detailed protocol for live vaccine production at scale has recently been published. However, quality control and delivery issues constrain vaccination sustainability and deployment. There is evidence that the distribution of T. parva is spreading from endemic areas in East Africa, North into Southern Sudan and West into Cameroon, probably as a result of anthropogenic movement of cattle. It has also recently been demonstrated that in Kenya, T. parva derived from cape buffalo can 'breakthrough' the immunity induced by ITM. However, in Tanzania, breakthrough has not been reported in areas where cattle co-graze with buffalo. It has been confirmed that buffalo in northern Uganda national parks are not infected with T. parva and R. appendiculatus appears to be absent, raising issues regarding vector distribution. Recently, there have been multiple field population genetic studies using variable number tandem repeat (VNTR) sequences and sequencing of antigen genes encoding targets of CD8+ T-cell responses. The VNTR markers generally reveal high levels of diversity. The antigen gene sequences present within the trivalent Muguga cocktail are relatively conserved among cattle transmissible T. parva populations. By contrast, greater genetic diversity is present in antigen genes from T. parva of buffalo origin. There is also evidence from several studies for transmission of components of stocks present within the Muguga cocktail, into field ticks and cattle following induction of a carrier state by immunization. In the short term, this may increase live vaccine effectiveness, through a more homogeneous challenge, but the long-term consequences are unknown.


Asunto(s)
Antígenos de Protozoos/inmunología , Búfalos/parasitología , Enfermedades de los Bovinos/prevención & control , Vacunas Antiprotozoos/inmunología , Theileria parva/inmunología , Theileriosis/prevención & control , Vacunación/veterinaria , África/epidemiología , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/parasitología , Portador Sano , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/terapia , Reservorios de Enfermedades/parasitología , Variación Genética , Genética de Población , Repeticiones de Minisatélite/genética , Epidemiología Molecular , Theileria parva/genética , Theileriosis/epidemiología , Theileriosis/parasitología , Theileriosis/terapia , Garrapatas/parasitología , Vacunas Atenuadas/inmunología
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