Changes in the motility, morphology, and F-actin architecture of human dendritic cells in an in vitro model of dendritic cell development

An in vitro model has been developed for analyzing the two developmental ph ases of human dendritic cell (DC) migration. Employing the age of the cultu re and the addition of GM-CSF, IL-4, and serum to regulate cellular phenoty pe, and glass coated with acid-precipitated human plasma proteins to facili tate persistent DC translocation, the model produces three sequential in vi tro phenotypes with the following suggested in vivo counterparts: (1) DCs r ecently isolated from blood, which are highly polar and motile, and reflect the behavior of "undifferentiated" DCs that must extravasate from the bloo d stream and migrate into peripheral tissue; (2) large, nonmotile, stellate DCs, which reflect the highly "differentiated" signature phenotype of DCs in peripheral tissue, whose function is to capture foreign antigens; and (3 ) the large, motile "dedifferentiated" DCs, which reflect the behavior of " veiled cells" that have captured an antigen, retracted dendritic processes, migrated out of peripheral tissue, and are in the process of transporting a captured antigen to a proximal draining lymph node for presentation to T cells. Computer-assisted motion analysis of the three sequential phenotypes and fluorescent staining of F-actin reveal three unique behavioral states and unique cellular architecture consistent with inferred in vivo function. This in vitro model should serve as a starting point for elucidating the c ues and molecular mechanisms involved in the regulation of DC differentiati on and motility. Cell Motil. Cytoskeleton 46:200-221, 2000. (C) 2000 Wiley- Liss, Inc.