[Expression of Foxp3 in CD4+CD25high Treg cells of neonatal cord blood].

Aim: To investigate the amount of CD4+CD25high Treg cells and the expression of Foxp3 in neonatal cord blood, and to analyze the expression of Treg cells in neonates.
Methods: The mononuclear cells from cord blood or peripheral blood were isolated from neonatal cord blood (n=15) or healthy adult's peripheral blood (n=12) by density gradient centrifugation. Then they were stained with fluorescence labeled monoclonal antibodies for cell surface and intracellular protein. The amount of CD4+CD25high Treg cells and intercellular transcription factor Foxp3 were measured by flow cytometry.
Results: The amount of CD4+CD25high Treg cells in CD3+CD4+ T cells in cord blood was significantly higher than that in adult's peripheral blood (3.86%+/-1.63% vs 0.87%+/-0.74%, P<0.01), whereas the expression of Foxp3 in CD4+CD25high Treg cells in cord blood was markedly lower than in adult's blood (23.21%+/-8.9% vs 71.3%+/-11.6%, P<0.01).
Conclusion: The low expression of Foxp3 in CD4+CD25high Treg cells in cord blood suggests Treg cells in neonates are not mature in suppression.