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- Dandouras, Iannis, et al.
(author)
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Titan's exosphere and its interaction with Saturn's magnetosphere
- 2009
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In: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 367:1889, s. 743-752
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Journal article (peer-reviewed)abstract
- Titan's nitrogen-rich atmosphere is directly bombarded by energetic ions, due to its lack of a significant intrinsic magnetic field. Singly charged energetic ions from Saturn's magnetosphere undergo charge-exchange collisions with neutral atoms in Titan's upper atmosphere, or exosphere, being transformed into energetic neutral atoms (ENAs). The ion and neutral camera, one of the three sensors that comprise the magnetosphere imaging instrument (MIMI) on the Cassini/Huygens mission to Saturn and Titan, images these ENAs like photons, and measures their fluxes and energies. These remote-sensing measurements, combined with the in situ measurements performed in the upper thermosphere and in the exosphere by the ion and neutral mass spectrometer instrument, provide a powerful diagnostic of Titan's exosphere and its interaction with the Kronian magnetosphere. These observations are analysed and some of the exospheric features they reveal are modelled.
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- Milling, S W F, et al.
(author)
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Steady-state migrating intestinal dendritic cells induce potent inflammatory responses in naive CD4+ T cells.
- 2009
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In: Mucosal immunology. - : Elsevier BV. - 1935-3456 .- 1933-0219. ; 2:2, s. 156-65
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Journal article (peer-reviewed)abstract
- Steady-state dendritic cells (DCs) migrating in the lymph from the intestine induce tolerance to harmless intestinal antigens, preventing inflammatory responses. To determine if such DCs are inherently tolerogenic we collected intestinal lymph DCs (L-DCs) by cannulation of the thoracic duct of rats after mesenteric lymphadenectomy, and examined their capacity to activate naive CD4+ lymphocytes in an allogeneic mixed leucocyte reaction. L-DCs stimulated strong proliferative responses, induced secretion of inflammatory cytokines including interferon-gamma, and induced FoxP3-positive lymphocytes to divide. To determine if the activated CD4+ T cells had been tolerized, they were rested and restimulated with irradiated splenocytes. The restimulated CD4+ T cells again proliferated and secreted inflammatory cytokines. These data demonstrate that the DCs, which migrate from the intestine in the steady state, are paradoxically able to induce strong inflammatory responses from naive T cells, despite their role in the maintenance of oral tolerance.
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