Protective immunity in the rat model of congenital toxoplasmosis and the potential of excreted‐secreted antigens as vaccine components

Zenner, Lionel; Estaquier, Jérǒme; Darcy, F.; Mäes, Pierrette; Càpron, André; Cesbron-Delauw, Marie-France

doi:10.1046/j.1365-3024.1999.00229.x

Cited by 70 publications

(38 citation statements)

References 35 publications

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“…Costa-Silva et al (2008) reported that ESA immunized mice had lower parasitaemia as well as longer survival then mice in the control group. Zenner et al (1999) have reported that purified ESA, namely GRA2 and GRA5, had a significant degree of organs' protection. Furthermore, a study conducted by Daryani et al (2003) showed that the ESA-F2 antigens could be used as a good candidate for the development of new immunization strategy against toxoplasmosis.…”

Section: Discussionmentioning

confidence: 99%

A comparative study between excretory/secretory and autoclaved vaccines against RH strain of Toxoplasma gondii in murine models

et al. 2013

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Toxoplasma gondii is an obligate intracellular protozoan that has a major importance in public health, in addition to veterinary medicine. Therefore, the development of an effective vaccine for controlling toxoplasmosis is an important goal. Excretory/secretory antigens (ESA), were previously identified as potential vaccine candidates, proved to play important roles in the pathogenesis and immune escape of the parasite. In addition, autoclaved Toxoplasma vaccine (ATV) is a special type of killed vaccine, recently characterized. The aim of the present work was, to compare between excretory/secretory and ATV against RH strain of T. gondii in mice based on; parasitological and histopathological levels. Tachyzoites were harvested from peritoneal exudates of infected mice and were used for challenge infection and vaccine preparation. BCG was used as an adjuvant. Mice were allocated equally into five groups; they were vaccinated intradermally over the sternum. The results of this study showed that the survival time after challenge, extended up to 16 days in ESA vaccinated group and up to 15 days in autoclaved Toxoplasma vaccinated group. ESA vaccinated group exhibited a profound decrease in parasite load following parasite challenge with a higher percentage of reduction in parasite count in all examined organs than the autoclaved Toxoplasma vaccinated group. The histopathological picture of the liver in both immunized groups, revealed marked reduction in the pathological changes observed as compared to controls, especially in ESA vaccinated group. It was concluded that vaccination with ESA showed more promising results versus ATV, as demonstrated by the survival rate of vaccinated mice, tachyzoites count and histopathological examination.

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Section: Discussionmentioning

confidence: 99%

A comparative study between excretory/secretory and autoclaved vaccines against RH strain of Toxoplasma gondii in murine models

et al. 2013

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“…A limitation of this model is the high susceptibility of certain strains of mice to toxoplasmosis, with a high rate of mortality during acute infection. Interestingly, in respect to clinical course and in utero transmission, toxoplasmoses in rats and humans are similar, and the infection in rats can serve as a model for human toxoplasmosis (6,26,(33)(34)(35). Hence, like humans, rats do not succumb to acute toxoplasmosis even with a high inoculum of Toxoplasma strains that are highly virulent in mice.…”

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confidence: 99%

Innate Refractoriness of the Lewis Rat to Toxoplasmosis Is a Dominant Trait That Is Intrinsic to Bone Marrow-Derived Cells

et al. 2005

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Toxoplasmosis is a ubiquitous parasitic infection causing a wide spectrum of diseases. It is usually asymptomatic but can lead to severe ocular and neurological disorders. Among the small-animal models available to study factors that determine susceptibility to toxoplasmosis, the rat appears to be rather similar to humans, particularly in terms of resistance to acute infection. Here, we demonstrate that the Lewis (LEW) rat strain displays an unexpected refractoriness to Toxoplasma infection. Complete resistance was assessed by both negative anti-Toxoplasma serology and lack of detection of the parasite during the course of infection. In this model, sex, age, major histocompatibility complex, and inoculum size had no effect on resistance. Interestingly, progeny from F 1 hybrid crosses between Fischer (F344) or Brown Norway susceptible rats and LEW resistant rats were also fully resistant, showing a dominant effect of the gene or set of genes. Furthermore, resistance of the LEW rat was shown to be dependent on hematopoietic cells and partially abrogated by neutralization of endogenous gamma interferon. To our knowledge, this is the first observation of a rodent strain that is refractory to Toxoplasma infection. This model is therefore an attractive and powerful tool to dissect host genetic factors involved in susceptibility to toxoplasmosis.Toxoplasma gondii is an obligate, intracellular parasite which can infect all mammals, including humans. In natural oral infection, the parasite initially crosses the intestinal barrier and disseminates, during the acute disease, as replicating cytolytic tachyzoites. The development of a vigorous immune response leads to a chronic infection characterized by the persistence of encysted parasites within the host's muscular and nervous tissues.In the human population, toxoplasmosis is usually asymptomatic, and substantial morbidity and mortality are most often found in immunocompromised patients (e.g., in those with AIDS, with organ transplants, or who received anticancer therapies) and in congenitally infected infants (10). Despite the fact that the host immunologic status is known to be critical in the outcome of Toxoplasma infection (7, 12), the severity of the disease caused by Toxoplasma infection varies widely depending on the host species (8, 30, 33) and remains unpredictable among individuals.Up to now, genetic studies on susceptibility to toxoplasmosis have been confined to the mouse model (2, 3, 23). A limitation of this model is the high susceptibility of certain strains of mice to toxoplasmosis, with a high rate of mortality during acute infection. Interestingly, in respect to clinical course and in utero transmission, toxoplasmoses in rats and humans are similar, and the infection in rats can serve as a model for human toxoplasmosis (6,26,(33)(34)(35). Hence, like humans, rats do not succumb to acute toxoplasmosis even with a high inoculum of Toxoplasma strains that are highly virulent in mice. In a comparative study using various strains of rats, we have previously s...

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“…The highest protection against congenital disease, however, was obtained in a rat model (Zenner et al 1999). However, in these models, the correlates of protection have not been elucidated.…”

Section: Discussionmentioning

confidence: 98%

Vaccines against Toxoplasma gondii: challenges and opportunities

Jongert

Roberts

Gargano

et al. 2009

Mem. Inst. Oswaldo Cruz

175

136

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Protective immunity in the rat model of congenital toxoplasmosis and the potential of excreted‐secreted antigens as vaccine components

Cited by 70 publications

References 35 publications

A comparative study between excretory/secretory and autoclaved vaccines against RH strain of Toxoplasma gondii in murine models

A comparative study between excretory/secretory and autoclaved vaccines against RH strain of Toxoplasma gondii in murine models

Innate Refractoriness of the Lewis Rat to Toxoplasmosis Is a Dominant Trait That Is Intrinsic to Bone Marrow-Derived Cells

Vaccines against Toxoplasma gondii: challenges and opportunities

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