A migratory population of skin-derived dendritic cells expresses CXCR5, responds to B lymphocyte chemoattractant in vitro, and co-localizes to B cell zones in lymph nodes in vivo.

Chemokine receptors on dendritic cells (DC) and chemokines within lymph nodes (LN) contribute to trafficking of DC to appropriate sites within the LN. Here we show that DC that have migrated out of skin ex vivo (migratory DC, migDC) express 50-fold more CXCR5 mRNA than fresh Langerhans cells and migrate in response to B lymphocyte chemoattractant (BLC) in vitro. When injected into the footpad of mice, migDC emigrate to regional LN where up to 40% are found in B cell zones. By contrast, murine bone marrow-derived DC display 14-fold less CXCR5, do not migrate to BLC in vitro, and migrate strictly to T cell zones in LN. We propose that activated skin DC utilize CXCR5 and BLC as a possible mechanism to home to B cell zones of LN, where they may have direct effects on B cells.