Immune System Modulation of Germinal and Parenchymal Neural Progenitor Cells in Physiological and Pathological Conditions

摘要: Historically, the Central Nervous System (CNS) was considered as an immune privileged site (Billingham and Boswell, 1953), being viewed a territory physiologically out of competence cells. This notion has developed on initial studies showing that: (i) CNS unrelated antigens (i.e. foreign grafts, bacteria, viruses) evade recognition when delivered to brain parenchyma (Galea et al., 2007); (ii) no infiltrating cells nor antigen presenting (APCs, i.e. dendritic cells, DCs, see Table 1) can be detected in physiological conditions (Engelhardt Ransohoff, 2005); (iii) do not constitutively express major histocompatibility complex (MHC)I MHCII molecules (Fabry 1994); (iv) neural apoptosis inductors for (Bechmann 1999); (v) does possess lymphatic vessels 2005). The segregation between nervous appeared tightly preserved by anatomical separations offered Blood Brain Barrier (BBB) blood-cerebrospinal fluid barrier (Choi Benveniste, 2004). Over time, basis association inflammation neurodegeneration, concept privilege further acquired connotation defence mechanism against detrimental effects activation within CNS.