title: CD4(+)CD25(+) regulatory T cells resist a novel form of CD28- and Fas-dependent p53-induced T cell apoptosis.
abstract: Ag receptor stimulation of preactivated T cells causes rapid cell death in an IL-2- and Fas-dependent manner. This phenomenon, known as activation-induced cell death (AICD), plays a pivotal role in the removal of Ag-reactive T cells after initial expansion. In this study, we report a novel form of T cell apoptosis that is distinct from classic AICD. When peripheral T cells were activated with anti-CD3 and anti-CD28 Abs precoated onto plastic plates, CD4(+)CD25(-) and CD8 T cells initially expanded but underwent massive apoptosis after 4 d. Unlike classic AICD, this type of T cell apoptosis pathway requires engagement of CD28 and expression of p53, a tumor-suppressor gene. The most striking feature of this form of apoptosis was regulatory T cell resistance. Under the same stimulating conditions, CD4(+)CD25(+) T cells grew continuously beyond 4 d. Consequently, when the entire CD4 population was cultured with plate-bound anti-CD3 plus anti-CD28 Ab, CD4(+)CD25(+)FoxP3(+) regulatory T cells outgrew nonregulatory T cells and expanded >7000-fold after 11 d. The data presented herein demonstrate a novel process of Ag-induced T cell death by sustained TCR and CD28 engagement and represent a simple and efficient procedure for the expansion of regulatory T cells in vitro.
authors: Immunotherapy Center, Medical College of Georgia, Augusta, GA 30912, USA.
authors: Nagendra
authors: N
authors: Singh
authors: Mutsumi
authors: M
authors: Yamamoto
authors: Mariko
authors: M
authors: Takami
authors: Yoichi
authors: Y
authors: Seki
authors: Mayuko
authors: M
authors: Takezaki
authors: Andrew L
authors: AL
authors: Mellor
authors: Makio
authors: M
authors: Iwashima
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D015153:Blotting, Western; D018106:CD28 Antigens / Q000276:immunology* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D051379:Mice; D018345:Mice, Knockout; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000276:immunology* / Q000378:metabolism; D019014:fas Receptor / Q000276:immunology* / Q000378:metabolism
chemical_list: D018106:CD28 Antigens; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor