Fractalkine induces chemotaxis and actin polymerization in human dendriticcells

Objective and design: Dendritic cells (DCs) are considered as the principle initiators of immune responses by virtue of their ability to migrate into target sites, process antigens and activate naive T cells. Here, the chemot actic activity and intracellular signaling of fractalkine was analyzed and compared to well known chemotaxins. Methods: The mRNA-expression of G protein-coupled CX3CR1 was analyzed by RT -PCR. Chemotaxis was measured in 48-well Boyden chambers and actin polymeri zation by flow cytometry. Results: The mRNA-expression of CX3CR1 in immature and mature DCs was revea led. Fractalkine elicited actin polymerization and chemotaxis in a dose-dep endent manner in DCs independent of their state of maturation. Conclusions: These results show that immature and mature DCs express mRNA f or the CX3CR1 and that fractalkine induces chemotaxis and migration associa ted actin polymerization in immature as well as in mature DCs, contrasting with the action of other chemokines such as RANTES or MIP-3beta which act o nly on distinct maturation states of DCs.