RESUMO
Objective:To establish and characterize human CD4 +CD25 + T cell lines Methods:CD4 +CD25 + T cells were isolated from healthy volunteers and expanded in vitro Their suppressive effect on the proliferation of CD4 + T cells was analyzed in proliferation assays Phenotype of the T cell lines was determined by FACS Results:Long term cultured CD4 +CD25 +T cells were hyporesponsive to stimulation via their T cell receptor In co culture experiments CD4 +CD25 + T cells could suppress the activation and proliferation of CD4 + T cells, and the suppression was abrogated when exogenous IL 2 was provided In vitro expanded human CD4 +CD25 + T cells remained positive for CD25 and CTLA 4 expression Conclusion:CD4 +CD25 + T cells can be established as long term cultured T cell lines while still maintaining their suppressive function and distinctive phenotype from CD4 +CD25 - T cells