Protective efficacy induced by DNA prime and recombinant protein boost vaccination with Toxoplasma gondii GRA14 in mice.

Toxoplasma gondii, the etiological agent of toxoplasmosis, can cause severe or lethal damages in both animals and man. So, tends to develop a more effective vaccine to prevent this disease is extremely needed and would be so prominent. The novel dense granule antigen 14 (GRA14) has been identified as a potential vaccine candidate against T. gondii infection. The aim of this study was evaluation of protective immunity induced by prime/boost vaccination strategy of GRA14 antigen with calcium phosphate (CaPNs) or Aluminum hydroxide (Alum) nano-adjuvants in BALB/c mice. The finding showed that immunization with the prime-boost strategy using plasmid DNA (pcGRA14) and recombinant protein (rGRA14) with nano-adjuvants significantly elicited levels of specific IgG antibodies and cytokines against T. gondii infection. Given that, there were the high levels of total IgG, IgG2a, IFN-γ in mice of rGRA14-CaPNs and pcGRA14 + rGRA14-CaPNs groups, which indicating a Th-1 type response. While immunization of mice with Alum based rGRA14 and pcGRA14 + rGRA14 elicited specific IgG1 and IL-4 levels, which was confirmed a Th-2 type response. Mice immunized with DNA prime-protein boost vaccine with nano-adjuvants produce more vigorous specific lymphoproliferative responses than mice immunized with other antigen formulations. In addition, the CaPNs-based prime-boost vaccine of pcGRA14 + rGRA14 showed the longest survival time in mice and the lowest parasitic load in their brain tissue compared to the other groups. The results obtained in this study show that the use of GRA14 based DNA prime-protein boost vaccination regime with CaPNs can dramatically enhanced both humoral and cellular immune responses. Therefore, this strategy can provide a promising approach to the development of an effective vaccine against T. gondii infection in the future.

Natural products applied against hydatid cyst protoscolices: A review of past to present.

Echinococcus granulosus is the causative agent of cystic echinococcosis (CE), which is distributed all around the world. CE is one of the most important global parasitic infectious diseases, both in humans and animals. This parasite causes hydatid cysts that can be lodge at different organs of host such as liver, lung even in heart and brain which may lead to death. Presently, numerous scolicidal chemical agents have been administrated for inactivation of the hydatid cyst contents. Because of increasing resistance and adverse effects of medications include abnormalities of liver function, abdominal pain, diarrhea, nausea, vomiting, dizziness, and headache; there is a need to find alternative therapies either with the least or without side effects. Recently, there is a high tendency among researchers to evaluate and present herbal plants as alternative option due to being inexpensive, easy available, low side effects and toxicity. Till now, many efforts have been conducted on herbal extracts against protoscolices of hydatid cysts throughout the world. Therefore, the current review systematically searched the following electronic databases: PubMed, Science Direct, Scopus, and Google Scholar on published papers according to the keywords. In addition, a comprehensive list of medicinal plants was prepared and some of these herbal plants which showed the best efficacy and promising results are discussed elaborately.

Enhancing immune responses to a DNA vaccine encoding Toxoplasma gondii GRA14 by calcium phosphate nanoparticles as an adjuvant.

Several approaches have been used to improve the immunogenicity of DNA vaccines. In the current study, we constructed the plasmid encoding T. gondii dense granule 14 (GRA14) and investigated the immunological properties of calcium phosphate nanoparticles (CaPNs) as nano-adjuvant to enhance the protective efficacy of pcGRA14. BALB/c mice intramuscularly injected three times at two-week intervals and the immune responses were evaluated using lymphocyte proliferation assay, cytokine and antibody measurements, survival times, and parasite load of mice challenged with the virulent T. gondii RH strain. The results showed that the immune responses were induced in mice receiving pcGRA14 DNA vaccine. Interestingly, pcGRA14 coated with nanoparticles led to statistically significant enhancements of cellular and humoral immune responses against Toxoplasma infection (P<0.05). After challenge with RH strain of T. gondii, immunized mice with pcGRA14 showed prolong survival time compared to control groups (P<0.05). In addition, pcGRA14 coated with nano-adjuvant exhibited the lowest parasitic load in the infected mice tissues. For the first time, our data indicate that the pcGRA14 coated with CaPN was more effective for stimulation of immune responses and should be considered as an adjuvant in the design of vaccines against toxoplasmosis.

Immunological evaluation of a DNA cocktail vaccine with co-delivery of calcium phosphate nanoparticles (CaPNs) against the Toxoplasma gondii RH strain in BALB/c mice.

Many recent studies have been conducted to evaluate protective immunity mediated by DNA vaccines against toxoplasmosis. Cocktail DNA vaccines showed better immune responses compared to single vaccines. The objective of the current study was to evaluate the protective efficacy of rhomboid 4 (ROM4) and cocktail DNA vaccines (ROM4 + GRA14) of the Toxoplasma gondii RH strain with or without coated calcium phosphate nanoparticles (CaPNs) as the adjuvant to improve the immunogenicity against the T. gondii RH strain in BALB/c mice. Cocktail DNA vaccines of pcROM4 + pcGRA14 of the T. gondii RH strain were constructed. CaPNs were synthesized and the cocktail DNA vaccine was coated with the adjuvant of CaPNs. Immunogenicity and the protective effects of cocktail DNA vaccines with or without CaPNs against lethal challenge were evaluated in BALB/c mice. pcROM4 and cocktail DNA vaccine coated with CaPNs significantly enhanced cellular and humoral immune responses against Toxoplasma compared to pcROM4 and cocktail DNA vaccine without CaPNs (p < 0.05). These findings indicate that the survival time of immunized mice after challenge with the RH strain of T. gondii was increased compared to that of controls and the DNA vaccine provided significant protection in mice (p < 0.05). The CaPN-based cocktail DNA vaccine of pcROM4 + pcGRA14 showed the longest survival time compared to the other groups. Co-immunization with CaPN-based cocktail DNA vaccine (pcROM4 + pcGRA14) boosted immune responses and increased the protective efficacy against acute toxoplasmosis in BALB/c mice compared to both single gene and bivalent DNA vaccine without nano-adjuvants.

The efficacy of herbal medicines against Toxoplasma gondii during the last 3 decades: a systematic review.

The objective of the current study was to systematically review papers discussing the efficacy of medicinal herbs against Toxoplasma gondii. Data were systematically collected from published papers about the efficacy of herbs used against T. gondii globally from 1988 to 2015, from PubMed, Google Scholar, ISI Web of Science, EBSCO, Science Direct, and Scopus. Forty-nine papers were included in the current systematic review reporting the evaluation of medicinal plants against T. gondii globally, both in vitro and in vivo. Sixty-one plants were evaluated. Most of the studies were carried out on Artemisia annua. The second highest number of studies were carried out on Glycyrrhiza glabra extracts. RH and ME49 were the predominant parasite strains used. Additionally, Swiss-Webster and BALB/c mice were the major animal models used. Alcoholic and aqueous extracts were used more than other types of extracts. Natural compounds mentioned here may be developed as novel and more effective therapeutic agents that improve the treatment of toxoplasmosis due to their lower side effects, higher availability, and better cultural acceptance compared with those of the chemical drugs that are currently being used.

Anti-Toxoplasma activities of methanolic extract of Sambucus nigra (Caprifoliaceae) fruits and leaves / Actividad anti-Toxoplasma de extractos metanólicos de frutos y hojas de Sambucus nigra (Caprifoliaceae)

Toxoplasma gondii is an obligatory intracellular parasite that infects a wide range of warm-blooded animals and humans. Considering the severity of toxoplasmosis, side effects of current treatments, and the contribution of the ethnopharmacological knowledge for the treatment of parasitic infections, the aim of the present study was to investigate the efficacy of methanolic extracts from the fruits and leaves of Sambucus nigra against tachyzoite of T. gondii. For this, fruits and leaves of S. nigra were collected from Mazandaran province, Iran, were dried under the shade, and powdered using a commercial electrical blender. For extractions, methanol was used as solvent. Virulent RH strain of T. gondii was maintained in mice and macrophages containing tachyzoites were aspirated from the peritoneal cavity. Four concentrations (5, 10, 25 and 50mg/mL) of S. nigra extract were incubated with infected macrophages for 30, 60, 120 and 180 minutes and the viability of the tachyzoites were evaluated by trypan blue staining. Results showed that S. nigra fruit extracts at the concentrations of 5 and 10mg/mL killed 100% of T. gondii tachyzoites after 60 and 120 minutes, respectively; and concentrations of 25 and 50mg/mL killed 100% of the tachyzoites after 30 minutes. Additionally, extract of S. nigra leaves, at the concentrations of 5, 10 and 25mg/mL after 180 minutes, and concentration of 50mg/mL after 60 minutes, resulted with the highest efficacy. Our results showed that S. nigra has acceptable efficacy in vitro and the parasiticidal effect of fruit extract was significantly better than leaf extract. However, in vivo efficacy of this extract needs further investigation. Rev. Biol. Trop. 63 (1): 7-12. Epub 2015 March 01.

Toxoplasma gondii es un parásito intracelular obligatorio que infecta a una gran variedad de animales y seres humanos. Teniendo en cuenta la gravedad de la toxoplasmosis, los efectos secundarios de los tratamientos actuales, y la contribución de los conocimientos etnofarmacológicos para el tratamiento de infecciones parasitarias, el objetivo del presente estudio fue investigar la eficacia de los extractos metanólicos de los frutos y hojas de Sambucus nigra contra el taquizoito de T. gondii. Para esto, se recogieron frutos y hojas de S. nigra en la provincia de Mazandaran, Irán, se secaron a la sombra, y se pulverizaron con una batidora eléctrica comercial. Para las extracciones, se empleó metanol como disolvente. La cepa virulenta RH de T. gondii se mantuvo en ratones y los macrófagos con taquizoitos se aspiraron de la cavidad peritoneal. Cuatro concentraciones (5, 10, 25 y 50mg/ mL) de extracto de S. nigra se encubaron con los macrófagos infectados durante 30, 60, 120 y 180 minutos y la viabilidad de los taquizoitos se evaluó mediante tinción con azul de tripano. Los resultados mostraron que los extractos de frutos de S. nigra en las concentraciones de 5 y 10mg/mL mataron al 100% de los taquizoitos de T. gondii después de 60 y 120 minutos, respectivamente; y las concentraciones de 25 y 50mg/mL mataron al 100% de los taquizoitos después de 30 minutos. Además, el extracto de hojas de S. nigra, en concentraciones de 5, 10 y 25mg/mL después de 180 minutos, y una concentración de 50mg/mL después de 60 minutos, resultaron más eficientes. Nuestros resultados mostraron que S. nigra tiene una eficacia aceptable in vitro y el efecto parasiticida del extracto de frutos fue significativamente mejor que el del extracto de hoja. Sin embargo, la eficacia in vivo de este extracto necesita más investigación.