Xiao Jianchun
Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Curr Top Behav Neurosci. 2023;61:303-313. doi: 10.1007/7854_2022_370.
Chronic infection with Toxoplasma gondii, a neurotropic parasite, has been linked to multiple behavioral changes in rodents and humans. The pathogenic mechanisms underlying these correlations are not known. I discuss here from animal studies the distribution of tissue cysts, the constant immune surveillance, the critical role of cyst burden, and the time-dependent consequences, which I believe are crucial to explaining the behavioral changes. In line with the brain-wide distribution of tissue cysts and chronic neuroinflammation, infected mice displayed a broad range of behavioral phenotypes. Many studies suggest that behavioral changes in mice are directly associated with tissue cyst presence or cyst burden and the host immune response. Cyst burden may not exert direct effects; however, the mechanisms causing behavioral and neuropathological changes are potentially the consequence of cyst burden over time, such as the neuroinflammation required to control the reactivation of tissue cysts. The reduction of neuroinflammation has proven that neuropathogenesis and behavioral abnormalities can be reversed, at least partially, in infected mice. Overall, Toxoplasma-induced behavioral changes are likely to be an indirect consequence of the host immune response in a parasite burden-dependent manner.
刚地弓形虫是一种嗜神经性寄生虫，其慢性感染与啮齿动物和人类的多种行为变化有关。这些相关性背后的致病机制尚不清楚。在此，我从动物研究的角度探讨组织囊肿的分布、持续的免疫监视、囊肿负荷的关键作用以及时间依赖性后果，我认为这些对于解释行为变化至关重要。与组织囊肿的全脑分布和慢性神经炎症一致，受感染的小鼠表现出广泛的行为表型。许多研究表明，小鼠的行为变化与组织囊肿的存在或囊肿负荷以及宿主免疫反应直接相关。囊肿负荷可能不会产生直接影响；然而，导致行为和神经病理变化的机制可能是囊肿负荷随时间推移的结果，例如控制组织囊肿再激活所需的神经炎症。神经炎症的减轻已证明，感染小鼠的神经病理发生和行为异常至少可以部分逆转。总体而言，弓形虫诱导的行为变化可能是以寄生虫负荷依赖的方式由宿主免疫反应间接导致的。
