Internalization and Accumulation in Dendritic Cells of a Small pH-Activatable Glycomimetic Fluorescent Probe as Revealed by Spectral Detection.

DC-SIGN, an antigen-uptake receptor in dendritic cell s( DCs), has ac lear role in the immune response but, conversely ,c an also facilitate infection by providing entry of pathogens into DCs. The key action in both processes is internalization into acidic endosomes and lysosomes. Molecular probes that bind to DC-SIG Nc ould thus provide au seful tool to study internalization and constitute potentia la ntagonists against pathogens. So far ,o nly large molecules have been used to directly observe DC-SIGN-mediated internalization into DC sb yf luorescence visualization. We designed and synthesized an appropriate small glycomimetic probe. Tw op articular properties of the probe were exploited :a ctivation in al ow-pH environmen ta nd an aggregation-induced spectra ls hift. Our results indicate that small glycomimetic molecules could compete with antigen/pathogen for binding not only outside but also inside the DC, thus preventing the harmful action of pathogens that are able to intrude into DCs, for example, HIV-1.