Clinical and Developmental Immunology 
Volume 2008 (2008), Article ID 305859, 12 pages
doi:10.1155/2008/305859
Research Article

Comparative Study of Regulatory T Cell Function of Human CD25+CD4+ T Cells from Thymocytes, Cord Blood, and Adult Peripheral Blood

Wakae Fujimaki,1,2,3 Nozomu Takahashi,1 Kei Ohnuma,1 Masayoshi Nagatsu,4 Hiromi Kurosawa,4 Satoko Yoshida,5 Nam H. Dang,6 Takehiko Uchiyama,2 and Chikao Morimoto1

 1Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
2Department of Microbiology and Immunology, Tokyo Women's Medical University, Tokyo 162-8666, Japan
3Human Medical Science Division, Kagawa Nutrition University, Saitama 350-0288, Japan
4Department of Cardiovascular Surgery, Tokyo Women's Medical University, Tokyo 162-8666, Japan
5Department of Obstetrics and Gynecology, Yoshida Clinic, Saitama 358-0054, Japan
6Department of Hematologic Malignancies, Nevada Cancer Institute, Las Vegas, NV 89135, USA
Received 13 February 2008; Revised 16 April 2008; Accepted 20 May 2008

Recommended by Yasunobu Yoshikai

Abstract

CD25+CD4+ regulatory T cells suppress T cell activation and regulate multiple immune reactions in in vitro and in vivo studies. To define the regulatory function of human CD25+CD4+ T cells at various stages of maturity, we investigated in detail the functional differences of CD25+CD4+ T cells from thymocytes, cord blood (CB), and adult peripheral blood (APB). CB CD25+CD4+ T cells displayed low-FOXP3 protein expression level and had no suppressive activity. In contrast, CD25+CD4+ T cells from thymocytes or APB expressed high expression level of FOXP3 protein associated with significant suppressive activity. Although CB CD25+CD4+ T cells exhibited no suppressive activity, striking suppressive activity was observed following expansion in culture associated with increased FOXP3 expression and a shift from the CD45RA+ to the CD45RA− phenotype. These functional differences in CD25+CD4+ T cells from Thy, CB, and APB hence suggest a pathway of maturation for Treg in the peripheral immune system.