Understanding how thymic selection imparts self-peptide-MHC complex restriction and a high degree of self tolerance on the T cell repertoire requires a detailed description of the parameters that shape the MHC ligand repertoire of distinct thymic antigen-presenting cells and of how these cells communicate with T cells. Several recent discoveries pertaining to cortex-specific pathways of antigen processing, the heterogeneity of thymic dendritic cells and the intercellular transfer of self antigens have uncovered surprising and unique aspects of antigen presentation in the thymic microenvironment.
[more] The tissues of the central nervous system are effectively shielded from the blood circulation by specialized vessels that are impermeable not only to cells, but also to most macromolecules circulating in the blood. Despite this seemingly absolute seclusion, central nervous system tissues are subject to immune surveillance and are vulnerable to autoimmune attacks. Using intravital two-photon imaging in a Lewis rat model of experimental autoimmune encephalomyelitis, here we present in real-time the interactive processes between effector T cells and cerebral structures from their first arrival to manifest autoimmune disease.
[more] Protective immunity against gastrointestinal and tissue dwelling helminths is coordinated by interaction of different effector cells of the innate and adaptive immune system. Helminths induce a strong type 2 immune response which is characterized by high levels of IgE and increased numbers of Th2 cells, eosinophils, mast cells and basophils. Basophils are rapidly mobilized after helminth infection and can be efficiently recruited into lymphoid and peripheral tissues where they execute their effector functions. Recent work demonstrated that basophils contribute to initiation and execution of type 2 immunity. This review discusses the potential role of basophils for protective immunity against helminths.
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