Gene expression analysis of CCL28 signaling in ishematopoietic stem and progenitor cells (HSPC) in culture

We identified chemokine (C-C motif) ligand 28 (CCL28) as a novel growth factor for HSPCs with the ability to enhance the proliferation potential of fetal, neonatal and adult CD34+ HSPCs after one week of culture in serum-free medium containing limiting stem cell factor (SCF) concentrations. Importantly, CCL28 could increase the progenitor potential of CB- and bone marrow (BM) derived CD34+ cells as measured by colony assays. Furthermore, treatment of CB CD34hiCD38loCD90+CD45RA- cells with CCL28 significantly enhanced the ability of the cells to long-term repopulate immunodeficient mice compared to SCF-treated cultures. Our findings show that CCL28 is a potent growth factor for human HSCs and suggest that it should be further exploited in clinical strategies for ex vivo expansion. Human CD34+CD38-CD45RAlowCD90+ cord blood cells were cultured in vitro for 18 hrs with CCL28 and SCF or SCF alone.