Differential responses of human regulatory T cells (Treg) and effector T cells to rapamycin

• Published in: PloS one 2009-06, Vol.4 (6), p.e5994-e5994
• Main Authors: Strauss, Laura, Czystowska, Malgorzata, Szajnik, Marta, Mandapathil, Magis, Whiteside, Theresa L
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 3-kinase; Annexin V; Antibiotics, Antineoplastic - pharmacology; Antibodies; Antigens; Apoptosis; Autoimmune diseases; Cancer; CD25 antigen; CD28 antigen; CD28 Antigens - biosynthesis; CD3 antigen; CD3 Complex - biosynthesis; CD4 antigen; CD4-Positive T-Lymphocytes - drug effects; CD4-Positive T-Lymphocytes - metabolism; CD8 antigen; Cell activation; Cell culture; Cell Proliferation; Cross-Linking Reagents - pharmacology; Cytokines; Effector cells; Expansion; Homeostasis; Human behavior; Humans; Immunology/Immune Response; Immunology/Immunomodulation; Immunology/Leukocyte Activation; Immunoregulation; Immunosuppressive agents; Immunotherapy; Interleukin 2; Interleukin 2 receptors; Interleukin Receptor Common gamma Subunit - metabolism; Interleukin-2 - metabolism; Interleukin-2 Receptor alpha Subunit - biosynthesis; Leukocytes, Mononuclear - cytology; Lymphocytes; Lymphocytes T; Medicine; Oncology/Head and Neck Cancers; Pathology; Peripheral blood mononuclear cells; Phosphatidylinositol 3-Kinases - metabolism; Protein binding; Protein expression; Proteins; PTEN protein; Rapamycin; Regulation; Signal Transduction; Signaling; Sirolimus - pharmacology; Stat3 protein; Stat5 protein; Survival; T cell receptors; T cells; T-cell receptor; T-Lymphocytes, Regulatory - drug effects; T-Lymphocytes, Regulatory - metabolism; TOR protein; Transplants & implants
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0005994

The immunosuppressive drug rapamycin (RAPA) promotes the expansion of CD4(+) CD25(high)Foxp3(+) regulatory T cells via mechanisms that remain unknown. Here, we studied expansion, IL-2R-gamma chain signaling, survival pathways and resistance to apoptosis in human Treg responding to RAPA. CD4(+)CD25(+) and CD4(+)CD25(neg) T cells were isolated from PBMC of normal controls (n = 21) using AutoMACS. These T cell subsets were cultured in the presence of anti-CD3/CD28 antibodies and 1000 IU/mL IL-2 for 3 to 6 weeks. RAPA (1-100 nM) was added to half of the cultures. After harvest, the cell phenotype, signaling via the PI3K/mTOR and STAT pathways, expression of survival proteins and Annexin V binding were determined and compared to values obtained with freshly-separated CD4(+)CD25(high) and CD4(+)CD25(neg) T cells. Suppressor function was tested in co-cultures with autologous CFSE-labeled CD4(+)CD25(neg) or CD8(+)CD25(neg) T-cell responders. The frequency and suppressor activity of Treg were increased after culture of CD4(+)CD25(+) T cells in the presence of 1-100 nM RAPA (p