Comparative evaluation of CC chemokine-induced migration of murine CD8 and CD8 – dendritic cells and their in vivo trafficking

Murine CD11c CD8 – and CD11c CD8 dendritic cells (DCs) differentially regulate T cell responses. Although specific chemokines that recruit immature (i) or mature (m) CD8 – DCs have been identified, little is known about the influence of chemokines on CD8 DCs. iDCs and mDCs isolated from spleens of fms-like tyrosine kinase 3 ligand-treated B10 mice were compared directly for migratory responses to a panel of CC chemokines or following local or systemic administration. In vitro assays were performed using Transwell chambers. iDCs did not respond to any CC chemokines tested. Both subsets of mDCs migrated to CCL19 and CCL21, with consistently lower percentages of CD8 DCs migrating. Chemokine receptor mRNA and protein expression were analyzed, but no correlation between expression and function was demonstrated. In vivo trafficking of fluorochrome-labeled DCs (B10; H2) was assessed by immunohistochemistry and by rare-event flow cytometric analysis of allogeneic recipient (BALB/c; H2) draining lymph node (DLN) and spleen cells. Twenty-four hours after intravenous injection, chloromethylfluorescein diacetate-positive CD8 and CD8 – mDCs were detected by immunohistochemistry in spleens in similar numbers (that decreased over time). Following subcutaneous injection, both DC subsets were detected in DLN at 24 h, but only CD8 – DCs were evident by flow analysis at 48 h. Although CD8 DCs migrate from peripheral tissues to T cell areas of (allogeneic) secondary lymphoid organs, they appear to mobilize as mDCs and less efficiently than CD8 – mDCs. J. Leukoc. Biol. 75: 000–000; 2004.