Rapid and coordinated switch in chemokine receptor expression during dendritic cell maturation

TLDR

Dendritic cells migrate into inflamed tissues, capture antigens, mature, and then travel to lymph nodes to activate T cells. The study compared chemokine receptor expression between immature and mature dendritic cells to understand maturation dynamics. Immature DC express CCR1, CCR2, CCR5, and CXCR1 and respond to their ligands, whereas maturation induces high CCR7 and CXCR4 expression, loss of surface CCR1/CCR5, and a shift toward lymphoid‑organ chemokine responsiveness, reflecting distinct inflammatory and primary‑response phases.

Abstract

Dendritic cells (DC) migrate into inflamed peripheral tissues where they capture antigens and, following maturation, to lymph nodes where they stimulate T cells. To gain insight into this process we compared chemokine receptor expression in immature and mature DC. Immature DC expressed CCR1, CCR2, CCR5 and CXCR1 and responded to their respective ligands, which are chemokines produced at inflammatory sites. Following stimulation with LPS or TNF-α maturing DC expressed high levels of CCR7 mRNA and acquired responsiveness to the CCR7 ligand EBI1 ligand chemokine (ELC), a chemokine produced in lymphoid organs. Maturation also resulted in up-regulation of CXCR4 and down-regulation of CXCR1 mRNA, while CCR1 and CCR5 mRNA were only marginally affected for up to 40 h. However, CCR1 and CCR5 were lost from the cell surface within 3 h, due to receptor down-regulation mediated by chemokines produced by maturing DC. A complete down-regulation of CCR1 and CCR5 mRNA was observed only after stimulation with CD40 ligand of DC induced to mature by LPS treatment. These different patterns of chemokine receptors are consistent with "inflammatory" and "primary response" phases of DC function.