Background:Few investigations of genotype II of Toxoplasma gondii,the most preva-lent form of the Toxoplasma parasite in humans,have been carried out on due to the rapid conversion of tachyzoites to bradyzoites in its...Background:Few investigations of genotype II of Toxoplasma gondii,the most preva-lent form of the Toxoplasma parasite in humans,have been carried out on due to the rapid conversion of tachyzoites to bradyzoites in its life cycle.The current study aimed to create animal and in vitro models for production of the tachyzoites of the Prugniaud(PRU)genotype II strain.Methods:To develop an immunocompromised model and obtain tachyzoites of the PRU strain,BALB/c mice were orally treated with dexamethasone(10 mg/kg),cyclo-phosphamide(36 mg/kg),and cyclosporine(18 mg/kg)from 5 days prior to inocula-tion.Then,10-15 tissue cysts of PRU strain were inoculated intraperitoneally into the mice.The tachyzoites obtained from mice were then cultivated in a HeLa cell culture.The resulting yield of tachyzoites was cryopreserved in 92%fetal calf serum,8%dimethyl sulfoxide.The infectivity of these tachyzoites was evaluated using in vivo and in vitro examinations.Results:Numerous tachyzoites were observed in the peritoneal fluid of the immuno-suppressed mice within 10-15 days after inoculation,and many tachyzoites were har-vested from the HeLa cell culture.Trypan Blue staining showed 80%viability of the tachyzoites recovered from cryopreservation and this was confirmed by HeLa cell culture.In addition,mice infected intraperitoneally with the recovered tachyzoites presented with cysts in the brain after 2 months.Conclusion:We have developed an animal model for mass production of T.gondii tachyzoites of the PRU strain.This method can provide fresh viable tachyzoites of Toxoplasma gondii for use as and when required in future investigations.展开更多
基金This research was funded by the project 97-01-01-18897 from Shiraz University of Medical Sciences,Shiraz,Iran.
文摘Background:Few investigations of genotype II of Toxoplasma gondii,the most preva-lent form of the Toxoplasma parasite in humans,have been carried out on due to the rapid conversion of tachyzoites to bradyzoites in its life cycle.The current study aimed to create animal and in vitro models for production of the tachyzoites of the Prugniaud(PRU)genotype II strain.Methods:To develop an immunocompromised model and obtain tachyzoites of the PRU strain,BALB/c mice were orally treated with dexamethasone(10 mg/kg),cyclo-phosphamide(36 mg/kg),and cyclosporine(18 mg/kg)from 5 days prior to inocula-tion.Then,10-15 tissue cysts of PRU strain were inoculated intraperitoneally into the mice.The tachyzoites obtained from mice were then cultivated in a HeLa cell culture.The resulting yield of tachyzoites was cryopreserved in 92%fetal calf serum,8%dimethyl sulfoxide.The infectivity of these tachyzoites was evaluated using in vivo and in vitro examinations.Results:Numerous tachyzoites were observed in the peritoneal fluid of the immuno-suppressed mice within 10-15 days after inoculation,and many tachyzoites were har-vested from the HeLa cell culture.Trypan Blue staining showed 80%viability of the tachyzoites recovered from cryopreservation and this was confirmed by HeLa cell culture.In addition,mice infected intraperitoneally with the recovered tachyzoites presented with cysts in the brain after 2 months.Conclusion:We have developed an animal model for mass production of T.gondii tachyzoites of the PRU strain.This method can provide fresh viable tachyzoites of Toxoplasma gondii for use as and when required in future investigations.
