To investigate specific properties of dendritic cells (DC) which are not shared by other antigen‐presenting cells, we compared gene expression patterns of mouse DC and macrophages by differential mRNA display. One of the cDNA identified coded for a murine homolog of the human β‐chemokine, thymus and activation‐regulated chemokine (TARC). The gene is expressed in a subset of bone marrow‐derived DC and is up‐regulated after lipopolysaccharide (LPS) stimulation. In vivo, murine TARC (mTARC) is constitutively expressed by thymic DC, lymphnode DC and CD11c⁺ cells in the lung. No expression was detected in bone marrow‐derived macrophages and LPS‐activated B cells. Recombinant mTARC has no chemoattractant activity on naive peripheral CD4⁺ T cells. In contrast, mTARC induced migration of primed ovalbumin‐specific CD4⁺ T cells with a preference for Th2 cells during the early phase of the T cell response. These observations suggest that mTARC directs migration of antigen‐experienced T helper cells to DC in lymphoid as well as in non‐lymphoid organs.