Ferguson D J, Hutchison W M
Nuffield Department of Pathology, University of Oxford, John Radcliffe Hospital, UK.
Parasitol Res. 1987;73(6):483-91. doi: 10.1007/BF00535321.
The ultrastructural features of the early development and tissue cyst formation of Toxoplasma gondii were examined in the brains of mice at various intervals from 7 days to 22 months post inoculation (PI). At 11 days PI toxoplasmas, with the ultrastructural features of the proliferative (endozoite) form, were identified undergoing multiplication within both inflammatory and neural cells. Early tissue cyst formation was also observed, predominantly within neurons. By 21 days PI the proliferative forms had disappeared and only developing tissue cysts containing densely packed cystozoites were present. The proportion of dividing cystozoites decreased with increasing size and age of the cysts. The wall of the tissue cyst developed as an adaptation of the lining of the parasitophorous vacuole. In the majority of older cysts, numerous tubular structures were present beneath the cyst wall. All the cysts observed were retained within intact host cells. The only morphological change with increasing age was that a proportion of the older cysts contained loosely packed cystozoites in an electron lucent ground substance. There was no evidence of any degenerative changes within the cystozoites.
在接种后7天至22个月的不同时间间隔，对小鼠大脑中弓形虫早期发育和组织囊肿形成的超微结构特征进行了检查。接种后11天，具有增殖（内殖子）形式超微结构特征的弓形虫在炎性细胞和神经细胞内均被发现正在增殖。还观察到早期组织囊肿形成，主要在神经元内。到接种后21天，增殖形式消失，仅存在含有密集排列的囊殖子的正在发育的组织囊肿。随着囊肿大小和年龄的增加，分裂的囊殖子比例下降。组织囊肿的壁是作为对寄生泡内衬的一种适应性发育而成。在大多数较老的囊肿中，囊肿壁下方存在许多管状结构。观察到的所有囊肿都保留在完整的宿主细胞内。随着年龄增长唯一的形态学变化是，一部分较老的囊肿在电子透明基质中含有排列松散的囊殖子。在囊殖子内没有任何退行性变化的证据。
