Comparative evaluation of CC chemokine‐induced migration of murine CD8α + and CD8α − dendritic cells and their in vivo trafficking

Murine CD11c + CD8α − and CD11c + CD8α + dendritic cells (DCs) differentially regulate T cell responses. Although specific chemokines that recruit immature (i) or mature (m) CD8α − DCs have been identified, little is known about the influence of chemokines on CD8α + 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 CD8α + 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 b ) was assessed by immunohistochemistry and by rare‐event flow cytometric analysis of allogeneic recipient (BALB/c; H2 d ) draining lymph node (DLN) and spleen cells. Twenty‐four hours after intravenous injection, chloromethylfluorescein diacetate‐positive CD8α + and CD8α − 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 CD8α − DCs were evident by flow analysis at 48 h. Although CD8α + DCs migrate from peripheral tissues to T cell areas of (allogeneic) secondary lymphoid organs, they appear to mobilize as mDCs and less efficiently than CD8α − mDCs.