• 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.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.