Expression of CC chemokine receptor 3 on human keratinocytes in vivo and in vitro upregulation by RANTES

CC chemokines and their ligands, CC chemokine receptors (CCRs), play an imp ortant role in the process of inflammation such as trafficking and activati ng inflammatory cells. CCR3 is known to be a ligand for CC chemokines such as RANTES, eotaxin and monocyte-chemotactic protein-3 (MCP-3). In this stud y we examined the expression of CCR3 in cultured normal human keratinocytes (KCs). CCR3 protein and mRNA expressions were detected in cultured normal KCs by flow cytometric (FACS) analysis and reverse-transcription-polymerase chain reaction (RT-PCR) analysis. FACS analysis demonstrated that CCR3 exp ression on KCs was significantly upregulated when the cells were cultured w ith RANTES, but not with eotaxin, IL-4 or interferon-gamma. RT-PCR analysis revealed that CCR3 mRNA was detectable in normal KCs. We also examined the immunoreactivity of CCR3 in normal skin and inflammatory skin lesions. CCR 3 was detected weakly in epidermis of normal skin, while strong immunoreact ivity for CCR3 was seen in epidermis of inflammatory skin lesions such as a topic dermatitis. These results suggest that CCR3 is constitutively express ed on KCs and is involved in inflammatory modulation. RANTES may regulate t he function of KCs through CCR3. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.