Activation of Immature Dendritic Cells Via Membrane Sialophorin (CD43)
Sialophorin (leukosialin, CD43) is a leukocyte membrane glycoprotein very rich in sialic acid residues and with an extended, mucine-like structure1. Various studies have suggested that CD43 is involved in the regulation of cell-cell interactions as an anti-adhesion molecule and that CD43 can mediate an independent pathway of cytoplasmic signaling and activation in monocytes, T and B lymphocytes2–4. Dendritic cells (DC) are the antigen presenting cells (APC) most efficient in the activation of naive T cells and in the induction of primary T cell-mediated immune responses. In unperturbed tissue, DC exhibit elevated antigen capture capacity but low APC activity (immature DC). Upon activation, DC increase expression of surface MHC and accessory molecules, and become very potent APC. The signals that drive DC maturation are bacterial products and cytokines such as TNF-a and IL-1f3. Maturation of DC, however, is completed only during antigen presentation by interactions between cell surface molecules expressed by T cells and DC (e.g., CD4OL/CD40) and cytokines released by T cells5. Unraveling the factors and the mechanisms involved in DC activation is a very important issue, not only for a better understanding of DC physiology, but also for developing more effective DC-based strategies in the immunotherapy of tumors and infections. In this study, we have investigated the expression and function of CD43 on epidermal Langerhans cells (LC) and in DC generated from peripheral blood monocytes incubated with GMCSF and IL-4 for 6–10 days (Mo-DC).6,7
KeywordsDendritic Cell Antigen Present Cell Dendritic Cell Maturation Immature Dendritic Cell Sialic Acid Residue
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