Objective To study the clonal heterogeneity in differentiation potential of immortalized mesenchymal stem cellsin vitro and in rive.Methods The monoclonal cell lines were performed with limiting dilutioncloning,and were induced to adipocytic,asteogenic and neuronal differentiation in vitro.After transplanted the monoclonal cell lines into SCID mice,the xenotransplants were removed and evaluated by immunohistochemistry.Results From the parental HMSC-TERT,32 single-cell derived clones were established,of which the differentiation properties varied considerably in vitro.The cells grow in different plating densities during expansion in cultureHMSC-TERT-2 expressed more strongly in LCA,GFAP and vimemin;HMSC-TERT-C19 expressed more strongly in keratinose than HMSC-TERT-2,HMSC-IERT-20,and MSC-H;HMSC-TERT-C2 expressed more strongly in actin than HMSC-TERT-2.Conclusions The HMSC-TERT monoclone cells are heterogeneity in differentiation petential in vitro and in vivo,suggesting that standard in vitroculture and in vivo inoculate procedure phy an important role in the clinical application of stem cells.