Transcription factor KLF2 regulates the migration of naive T cells by restricting chemokine receptor expression patterns.

The migration patterns of naive and activated T cells are associated with the expression of distinct sets of chemokine receptors, but the molecular basis for this regulation is unknown. Here we identify Krupple-like factor 2 (KLF2) as a key transcriptional factor needed to prevent naive T cells from expressing inflammatory chemokine receptors and acquiring the migration patterns of activated T cells. Lineage-specific deletion of KLF2 resulted in fewer naive T cells in the blood and secondary lymphoid organs, whereas it expanded naive T cell numbers in nonlymphoid tissues; these effects were associated with altered expression of inflammatory chemokine receptors on naive T cells. KLF2 repressed the expression of several chemokine receptors, including CCR3 and CCR5. We thus conclude that KLF2 maintains proper T cell migration patterns by linking T cell movement and transcriptional regulation of chemokine receptor expression patterns.