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William Harvey Research Institute, Barts and The London Medical School, London, UK
1Correspondence: The William Harvey Research Institute, Barts and The London School of Medicine, Charterhouse Sq., London EC1M 6BQ, UK. E-mail: f.dacquisto{at}qmul.ac.uk
Dendritic cells play a key role in the adaptive immune system by influencing T-cell differentiation. Annexin-1 (Anx-A1) has recently been shown to modulate the adaptive immune response by regulating T-cell activation and differentiation. Here we investigated the role of endogenous Anx-A1 in dendritic cells as major cellular counterpart of T-cell-driven immune response. We found that Anx-A1–/– bone marrow-derived dendritic cells show an increased number of CD11c+ cells expressing high levels of some maturation markers, such as CD40, CD54, and CD80, coupled to a decreased capacity to take up antigen compared to control Anx-A1+/+ cells. However, analysis of LPS-treated dendritic cells from Anx-A1–/– mice demonstrated a diminished up-regulation of maturation markers, a decreased migratory activity in vivo, and an attenuated production of the inflammatory cytokines interleukin (IL)-1β, tumor necrosis factor (TNF)-
, and IL-12. This defect was also accompanied by impaired nuclear factor (NF)-
B/DNA-binding activity and lack of Anx-A1 signaling, as demonstrated by the reduced activation of extracellular-signal regulated kinase (ERK)1/2 and Akt compared to cells from control littermates. As a consequence of this phenotype, Anx-A1–/– dendritic cells showed an impaired capacity to stimulate T-cell proliferation and differentiation in mixed leukocyte reaction. Together, these findings suggest that inhibition of Anx-A1 expression or function in dendritic cells might represent a useful way to modulate the adaptive immune response and pathogen-induced T-cell-driven immune diseases.—Huggins, A., Paschalidis, N., Flower, R. J., Perretti, M., D'Acquisto, F. Annexin-1-deficient dendritic cells acquire a mature phenotype during differentiation.
Key Words: inflammation antigen presenting cells formyl peptide receptor ligand
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