| Popis: |
Infection with Toxoplasma gondii is characterised by an acute phase, associated with the rapid proliferation of tachyzoites, followed by a chronic phase during which the slow-growing bradyzoite stage forms cysts in brain and muscle tissue. Although tissue cysts are often refered to as ‘dormant’, there is evidence of bradyzoite turnover within the cyst (Pavesio et al. 1992) and of periodic cyst rupture (Ferguson et al. 1989). Bradyzoites released from the cyst may convert into tachyzoites causing recrudesence of acute disease which, in immunosuppressed individuals, can be fatal (Luft and Remington 1992). Control of disease relies upon recognition and immunoregulation of both stages and it is therefore important to have an understanding of the comparative antigenic structure of tachyzoites and bradyzoites. |
