[Cryopreservation of Toxoplasma gondii tachyzoites and tissue cysts].

Toxoplasma gondii tachyzoites and tissue cysts are largely used for developing diagnostic assays, vaccines and in drug research as well as biochemical and molecular structure studies. Continuous passaging of tachyzoites or tissue cysts in animal models encounter ethical and economical problems and it is a time consuming procedure. Cryopreservation of tachyzoites and tissue cysts and revitalization of cryopreserved samples whenever needed, can decrease the economical loss, ethical problems and labour. In the present article, production of tachyzoites and tissue cysts in mice, preparation of samples for cryopreservation, cryopreservation of tachyzoites and tissue cysts, defrosting of cryopreserved samples and reinoculation to mice have been described in detail.