Department of Biology, South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249-1644, USA.
Curr Top Microbiol Immunol. 2009;336:83-104. doi: 10.1007/978-3-642-00549-7_5.
Parasite infections in the central nervous system (CNS) are a major cause of morbidity and mortality worldwide, second only to HIV infection. Finding appropriate therapeutic measures to control CNS parasite infections requires an understanding of the tissue-specific host response. CNS parasitic diseases are invariably associated with persistent T-helper 1 (Th1) cytokine-dependent proinflammatory responses. Although type 1 cytokine-dependent proinflammatory responses are essential to control several types of parasite infections, their persistent production contributes to the development of neuropathology with severe consequences. A family of proteins called Toll-like receptors (TLRs) plays a pivotal role in the induction of inflammatory cytokines during infections and tissue injury. Accumulating evidence indicates that in several CNS parasitic infections such as toxoplasmosis and sleeping sickness, host responses mediated through TLRs contribute to parasite clearance and host survival. However, TLR-mediated responses can also contribute to disease severity, as exemplified in cerebral malaria, neurocysticercosis and river blindness. Thus, TLRs influence the immunopathogenesis of CNS parasitic infections by mechanisms that can either benefit the host or further contribute to CNS pathology. This chapter discusses the immunopathogenesis of parasitic infections in the CNS and the role of TLRs in this process.
中枢神经系统（CNS）寄生虫感染是全世界发病率和死亡率的主要原因，仅次于 HIV 感染。找到控制中枢神经系统寄生虫感染的适当治疗措施需要了解组织特异性宿主反应。中枢神经系统寄生虫病总是与持续的 Th1（辅助性 T 细胞 1）细胞因子依赖性促炎反应有关。尽管依赖于 1 型细胞因子的促炎反应对于控制几种类型的寄生虫感染至关重要，但它们的持续产生导致严重后果的神经病理学发展。一组称为 Toll 样受体（TLR）的蛋白质在感染和组织损伤过程中诱导炎症细胞因子的产生中起着关键作用。越来越多的证据表明，在几种中枢神经系统寄生虫感染（如弓形虫病和昏睡病）中，通过 TLR 介导的宿主反应有助于清除寄生虫并维持宿主存活。然而，TLR 介导的反应也可能导致疾病的严重程度，如脑疟疾、神经囊虫病和河盲症。因此，TLR 通过可以使宿主受益或进一步导致中枢神经系统病理的机制影响中枢神经系统寄生虫感染的免疫发病机制。本章讨论了中枢神经系统寄生虫感染的免疫发病机制以及 TLR 在这一过程中的作用。
