| |
|
|
|
|
|
|
|||
|
Blood, 1 April 2008, Vol. 111, No. 7, pp. 3615-3625. Prepublished online as a Blood First Edition Paper on January 25, 2008; DOI 10.1182/blood-2007-09-111179.
IMMUNOBIOLOGY Shedded neuronal ICAM-5 suppresses T-cell activation1 Division of Biochemistry, Department of Biologic and Environmental Sciences, Faculty of Biosciences, University of Helsinki, Helsinki; 2 Wihuri Research Institute, Helsinki; and 3 Neuroscience Center, University of Helsinki, Helsinki, Finland
Intercellular adhesion molecules (ICAMs) bind to leukocyte β2 integrins, which, among other functions, provide costimulatory signals for T-cell activation. ICAM-5 (telencephalin) is expressed in the somadendritic region of neurons of the mammalian brain. The receptor for ICAM-5 is the integrin LFA-1, a major leukocyte integ-rin expressed in lymphocytes and microglia. In conditions of brain ischemia, epilepsy, and encephalitis, the soluble form of ICAM-5 (sICAM-5) has been detected in physiologic fluids. Here, we report that sICAM-5 attenuates the T-cell receptor-mediated activation of T cells as demonstrated by the decreased expression of the activation markers CD69, CD40L, and CD25 (IL-2R). This effect is most clearly seen in CD45ROLow (naive), and not in CD45ROHigh (memory) T cells, and is most effective early in priming, but not in the presence of strong costimulatory signals. Furthermore, sICAM-5 promotes the mRNA expression of the cytokines TGF-β1 and IFN-
This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Copyright © 2008 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||