Differential responsiveness to constitutive vs. inducible chemokines of immature and mature mouse dendritic cells

Upon exposure to immune or inflammatory stimuli, dendritic cells (DC) migra te from peripheral tissues to lymphoid organs, where they present antigen. The molecular basis for the peculiar trafficking properties of DC is largel y unknown. In this study, mouse DC were generated from CD34(+) bone marrow precursors and cultured with granulocyte-macrophage-CSF and Flt3 ligand for 9 days. Chemokines active on immature DC include MIP1 alpha, RANTES, MIP1 beta, MCP-1, MCP-3, and the constitutively expressed SDF1, MDC, and ELC, TN F-alpha-induced DC maturation caused reduction of migration to inducible ch emokines (MIP1 alpha, RANTES, MIP1 beta, MCP-1, and MCP-3) and increased mi gration to SDF1, MDC, and ELC, Similar results were obtained by CD40 Ligati on or culture in the presence of bacterial lipopolysaccharide, TNF-alpha do wn-regulated CC chemokine receptor (CCR)1, CCR2, and CCR5 and up-regulated CCR7 mRNA levels, in agreement with functional data. This study shows that selective responsiveness of mature and immature DC to inducible vs. constit utively produced chemokines can contribute to the regulated trafficking of DC.