Revisiting the Mechanisms of CNS Immune Privilege

Abstract

Whereas the study of the interactions between the immune system and the central nervous system (CNS) has often focused on pathological conditions, the importance of neuroimmune communication in CNS homeostasis and function has become clear over that last two decades. Here we discuss the progression of our understanding of the interaction between the peripheral immune system and the CNS. We examine the notion of immune privilege of the CNS in light of both earlier findings and recent studies revealing a functional meningeal lymphatic system that drains cerebrospinal fluid (CSF) to the deep cervical lymph nodes, and consider the implications of a revised perspective on the immune privilege of the CNS on the etiology and pathology of different neurological disorders.

Role of nitric oxide in the regulation of immune responses during rabies virus infection in mice

“…T lymphocytes and NK cells in blood and spleen might be due to immune response directed against rabies virus by the host after exposure to prevent viral replication [39]. The activation of naive T and B cells in peripheral secondary lymphoid organs occurs during viral infections of CNS and activated T cells will cross the BBB to reach the CNS [7][8][9]. Further, nucleocapsid of RABV acted as super antigen in mice and resulted in stimulation of T cell proliferation, and also decreased nitric oxide levels up to 4 DPI could be the reasons for early increased immune cells in blood and spleen [16,23].…”

“…This stimulates antigen-specific activation of naive lymphocytes in lymphoid organs and reactivation of lymphoblasts that have migrated into the CNS. The initial peripheral immune response to CNS-derived antigen is characterized by strong antibody response and cytotoxic T cell responses [7,8]. Activated T cells routinely cross the blood brain barrier (BBB) as part of the normal immunological surveillance of all tissues [9].…”

Transplantation in the nonhuman primate MPTP model of Parkinson's disease: update and perspectives

“…The brain has long been positioned as immune privileged, but it is now well established that this privilege is not absolute and that immunological rejection processes can occur in the CNS (Lindvall, 1989;Cicchetti et al, 2003;Louveau et al, 2015). Transplanted tissue or cells might thus be recognized as foreign, leading to their rejection after transplantation in the brain.…”

CSF/serum matrix metallopeptidase‐9 ratio discriminates neuro Behçet from multiple sclerosis

“…Due to its physiological role, cerebrospinal fluid (CSF) gives information on chemokines and cytokines that in part mediate neurologic autoimmune diseases 3, 4, 5. In NBD, CSF cytokines and chemokines (i.e., IL6, CXCL8, IL10, IL15, IFN γ , and TNF α ) have been correlated with pathogenesis together with Th1 and Th17 cell polarization without identifying a unique combination of cell population/soluble factors6, 7, 8; all these studies indicate a complex mechanism behind the disease.…”