• Parasites, Hosts and Diseases
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• v.32 no.3
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• pp.185-194
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• 1994

The present study was undertaken to assess the role of cytokines in the activation of peritoneal macrophages from Toxoplasma-infected mice. Peritoneal macrophages from Toxoplasma-infected mice (10 cysts of Beverley strain/mouse) were harvested 8 weeks after infection, and incubated with the mitogen-induced lymphokine, recombinant mouse $interferon-{\gamma}(IFN-{\gamma})$, recombinant mouse tumor necrosis $factor-{\alpha}{\;}(TNF-{\alpha})$ alone or in combination with 4$IFN-{\gamma}(IFN-{\gamma}/TNF-{\alpha})$ for 24hr at 37^{\circ}C$, 5% $CO_2$. Macrophage activation was measured by the amount of $H_20_2{\;}and{\;}N0_2^{-}$ production, and antiToxoplasma activities of macrophages. $IFN-{\gamma}{\;}or{\;}IFN-{\gamma}/TNF-{\alpha}-treated$ macrophages from Toxoplasma-infected mice revealed significantly higher $H_20_2$ production than resident macrophages from Toxoplasma-infected mice. The production of $N0_2^{-}{\;}by{\;}TNF-{\alpha}-,{\;}IFN-{\gamma}-{\;}or{\;}IFN-{\gamma}/TNF-{\alpha}-treated$ macrophages from Toxoplasma-infected mice were significantly higher than that by resident macrophages, whereas lymphokine-treated group produced similar amount as that produced by resident macrophages. Anti-Toxoplasma activities of cytokinetreated macrophages from Toxoplasma-infected mice were Significantly higher than those of resident macrophages. $IFN-{\gamma}-treated$ macrophages were significantly increased production of $H_20_2{\;}and{\;}N0_2^{-}$, and anti-Toxoplasma activities of macrophages between normal and Toxoplasma-infected mice, whereas the other cytokine-treated groups were not significant differences between them. These data suggested that IFN-{\gamma}was the only one of cytokines capable of significantly activating the peritoneal macrophages from Toxoplasmainfected mice.

• Parasites, Hosts and Diseases
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• v.31 no.4
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• pp.363-370
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• 1993

This study was performed to evaluate the prophylactic effects of trimethoprim- sulfamethoxazole (TMP-SMZ) In mice experimentally infected with virulent RH strain and avirulent Beverley strain of T dognii. The mice infected with $1{\times}10^5$ tachyzoltes were used In the measurement of mean survival days, and the mice infected with 10 cysts were used In the tltratlons of specific antibodies and enumeration of brawn cysts. Mean survival days of mice were significantly increased In mice treated with TMP-SMZ as compared with splramycln-treated and untreated control group. Mean survival days and survival rates of mice were Increased according to the Increment of dosages, and TMP-SMZ protected 100% of mice after fifteen daily dose of 24 mg/mouse or more admlnlsted orally. Toxoplasma-specific serum IgG and IgM antibody titers were slgnlflcantly lower in mice treated with TMP-SMZ than those of splramycln-treated and untreated control group. Toxoplosma cysts were not found In mice treated with TMP-SMZ at a dose of 24 mg/mouse or more per day but the group of splramycin treatment and untreated controls were found in the brain from 20 days after Infection. The present results revealed that TMP-SMZ can be used as a prophylactic agent against murine toxoplasmosls after Intraperitoneally challenges with the virulent or avlrulent strain of T. gondii.

• Parasites, Hosts and Diseases
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• v.30 no.2
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• pp.125-132
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• 1992

This study was performed to observe the cell-mediated and humoral immune responses in mice which were infected with Beverley, Fukaya and ME49 strain of Toxoplasma gondii, respectively. The blastogenic responses of splenocytes using $[^3H]-thymidine$ and serum antibody titers were measured weekly up to 10 weeks after infection. The blastogenic responses of splenocytes treated with concanavalin A and Tosoplasma Iysate were significantly declined in the 3 strain groups as compared with the non-infected group (P<0.05), however lipopolysaccharide-treated blastogenic responses were not significantly different between infected and non.infected groups. The serum IgG antibody titers in the three infected groups increased from 2 weeks after infection, and the serum IgM antibody titers increased until 4 weeks after infection. No significant differences were revealed in blastogenic responses and serum antibody titers among the 3 groups. The present study suggested that cell-mediated immune responses were involved in T. gondii infected mice and blastogenic responses of T Iymphocytes were inhibited in acute T. gondii infection.

• Parasites, Hosts and Diseases
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• v.31 no.1
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• pp.31-36
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• 1993

This study was performed to evaluate differences of T cell subsets according to the injection period of recombinant mouse $interferon-{\gamma}{\;}(IFN-{\gamma}$ in acute Toxoplasma gondii infection. Each mouse was infected intraperitoneally with 100 cysts of Beverley strain T. gondii, and injuten with $5{\;}{\times}{\;}10^4$ units of $IFN-{\gamma}$ every other day two tares. The percentage of Thy-1, 2 cells and L3T4/Ly-2 cell ratio were significantly increased in the mice that received two doses of $IFN-{\gamma}$ on days 2 and 0 before infection, or days 0 and 2 after infection. The percentage of Ly-2 cells decreased in the $IFN-{\gamma}$ injected groups at th\ulcorner 3rd and 4th week after infection. The results suggest that administration of $IFN-{\gamma}$ to T gonnii-infected mice improves the changed population of T cell subsets to a normal state, especially when $IFN-{\gamma}$ was infected just after the infection.

• Parasites, Hosts and Diseases
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• v.33 no.3
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• pp.201-210
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• 1995

This study aims to assess the possible strain-dependent variations in detection of ToxopLosmn antigens and antibodies. The virulent RH strain or avirulent Beverley strain of T gondii were injected into mice, intraperitoneally, and their antigens, antibodies and parasites were identified from the blood or tissues: liver, brain and spleen by ELISA, Western blot and PCR. In mice infected with RH strain, circulating antigens and parasitemia were first detected from 2 days after infection, and ToxopIasma DNA were found in the blood, liver, brain and spleen from 3 days after infection. It was impossible to detect specific IgM and IgG antibodies to T gondij and any specific band was not found by Western blot. In mice infected with Beverley strain, circulating antigens were detected between day 10 and day 35. The Toxoplusma DNA was found in the blood and liver from day 15 until day 60, and in the brain from day 20. But Toxoplosma DNA in the spleen were mainly detected between day 10 and day 30. The IgM antibodies were first appeared on day 10 post-infection, and were noted obviously increased between day 15 and 25. The IgG antibodies were first detected on day 15, and showed progressively increased titers. The antibody binding bands were specific according to infection period. Sera from mice infected with Beverley strain reacted mainly with the antigen of 27.5-kDa and 32.5-kDa. In conclusion, mice infected with RH strain revealed Toxoplosma antigens strongly, but not antibodies. However. mice infected with Beverley strain revealed both the Toxoplasma antigens and antibodies. The present results showed that immune responses are different between avirulent and virulent T gonnii.