Histopathology of murine toxoplasmosis under treatment with dialyzable leukocyte extract.

BACKGROUND: Dialyzable leukocyte extracts (DLEs) contain molecules smaller than 10 kDa with biological activity in receptor organisms. Primarily, they participate in the regulation of the Th1 immune response, which is essential for the control of several intracellular infections, such as toxoplasmosis. This disease is associated with congenital infection, encephalitis or systemic infections in immunocompromised individuals. The clinical course of this infection fundamentally depends on a well-regulated immune response and timely treatment with the appropriate drugs. OBJECTIVE: The aim of this study was to evaluate the effect of treatment with a leukocyte extract, derived from crocodile lymphoid tissue, on the histopathology and brain parasite load in NIH mice that had been infected with cysts of Toxoplasma gondii (ME-49 strain). METHODS: The treatment was applied during the acute and chronic stages of the infection. Histopathological changes were evaluated in the ileum, liver and spleen at one, four and eight weeks after infection and in the brain at week 8. The parasite load was evaluated by counting the cysts of T. gondii found in the brain. FINDINGS: Compared to the control mouse group, the mice infected with T. gondii and under treatment with DLE showed less tissue damage, mainly at the intestinal, splenic and hepatic levels. In addition, a greater percentage of survival was observed, and there was a considerable reduction in the parasite load in the brain. CONCLUSIONS: The results suggest that DLE derived from crocodile is a potential adjunctive therapy in the conventional treatment of toxoplasmosis.

Histopathology of murine toxoplasmosis under treatment with dialyzable leukocyte extract

BACKGROUND Dialyzable leukocyte extracts (DLEs) contain molecules smaller than 10 kDa with biological activity in receptor organisms. Primarily, they participate in the regulation of the Th1 immune response, which is essential for the control of several intracellular infections, such as toxoplasmosis. This disease is associated with congenital infection, encephalitis or systemic infections in immunocompromised individuals. The clinical course of this infection fundamentally depends on a well-regulated immune response and timely treatment with the appropriate drugs. OBJECTIVE The aim of this study was to evaluate the effect of treatment with a leukocyte extract, derived from crocodile lymphoid tissue, on the histopathology and brain parasite load in NIH mice that had been infected with cysts of Toxoplasma gondii (ME-49 strain). METHODS The treatment was applied during the acute and chronic stages of the infection. Histopathological changes were evaluated in the ileum, liver and spleen at one, four and eight weeks after infection and in the brain at week 8. The parasite load was evaluated by counting the cysts of T. gondii found in the brain. FINDINGS Compared to the control mouse group, the mice infected with T. gondii and under treatment with DLE showed less tissue damage, mainly at the intestinal, splenic and hepatic levels. In addition, a greater percentage of survival was observed, and there was a considerable reduction in the parasite load in the brain. CONCLUSIONS The results suggest that DLE derived from crocodile is a potential adjunctive therapy in the conventional treatment of toxoplasmosis.

The intraperitoneal inoculation of Lactobacillus casei in mice induces total protection against Trichinella spiralis infection at low challenge doses.

The following effects of Lactobacillus casei in NIH mice were evaluated: the establishment of Trichinella spiralis adult worms in the intestine (AWI), larvae per gram of muscle tissue (LPG), levels of IgG and IgA, and levels of IL-4 and IFN-γ. One hundred and eight mice were allocated at random into 18 groups of six mice each. Each mouse in treated or non-treated groups was inoculated intraperitoneally once a week during 6 weeks with L. casei or phosphate-buffered solution. Later each mouse was challenged either with 200, 50, or 25 T. spiralis infective larvae. When the infection dose was 200 T. spiralis infective larvae, the reductions in AWI were 78.6% at 4 days after infection (dai) and 76.7% at 10 dai; while the reduction of LPG was 80.9% with respect to control groups. When the infection dose was 50 or 25 T. spiralis infective larvae, the reductions of AWI were 100% both at 4 and 10 dai; while the reduction of LPG at 30 dai was also 100% with respect to control groups. The levels of IgG and IgA anti-T. spiralis and IL-4 were significantly higher (P < 0.01) at 4 and 10 dai in mice from groups treated with L. casei than in animals in control groups; while at 10 dai, the levels of IFN-γ were higher in control mice (P < 0.01) than in L. casei-treated animals. The results suggest that frequent treatment of mice with L. casei induces a total protection against infection with low doses of T. spiralis.