CD4+ CD25+ T cells are a population of regulatory T cells responsible for active suppression of autoimmunity. Specifically, CD4+ CD25+ T cells have been shown to prevent insulin-dependent diabetes mellitus, inflammatory bowel disease, and pancreatitis. Here, we present evidence that CD4+ CD25+ T cells also play a major role in controlling the severity of arthritis detected in Borrelia burgdorfe...

The long-term immunologic effects of intermittent interleukin 2 (IL-2) therapy were evaluated in a cross-sectional study by comparing 3 groups: HIV-seronegative volunteers, HIV-infected (HIV(+)) patients receiving highly active antiretroviral therapy (HAART), and HIV(+) patients receiving HAART and intermittent IL-2. Whole-blood immunophenotyping was performed to study expression of the IL-2 re...

BACKGROUND AND OBJECTIVES Graft-versus-host disease (GvHD) remains a major complication of allogeneic stem cell transplantation (SCT) and donor lymphocyte infusions (DLI). CD25-expressing donor T cells may be involved in the prevention or induction of GvHD as these cells comprise both CD4 +CD25+ regulatory T (Treg) cells and preactivated CD4+ or CD8+ conventional T cells. Therefore, we evaluate...

Chronic hepatitis C virus (HCV) infection is associated with impaired proliferative, cytokine, and cytotoxic effector functions of HCV-specific CD8(+) T cells that probably contribute significantly to viral persistence. Here, we investigated the potential role of T cells with a CD4(+)CD25(+) regulatory phenotype in suppressing virus-specific CD8(+) T-cell proliferation during chronic HCV infect...

Regulatory T cells are found primarily in the CD4(+) CD25(+) fraction of T cells and play an important role in the prevention of autoimmunity. We examined CD4(+) CD25(+) T cells in 33 healthy children and adults and compared them to a population with an inherited form of thymic hypoplasia and a predisposition to autoimmune disease. Absolute numbers of CD4(+) CD25(+) T cells were markedly higher...

CD7 and CD28 are T cell Ig superfamily molecules that share common signaling mechanisms. To determine roles CD7 and CD28 might play in peripheral lymphocyte development and function, we have generated CD7/CD28-double-deficient mice. CD7- and CD28-single-deficient and CD7/CD28-double-deficient mice had normal levels of CD4 and CD8-single-positive T cells in thymus and spleen. However, CD28-defic...

Interleukin (IL)-2 plays a crucial role in the maintenance of natural immunologic self-tolerance. Neutralization of circulating IL-2 by anti-IL-2 monoclonal antibody for a limited period elicits autoimmune gastritis in BALB/c mice. Similar treatment of diabetes-prone nonobese diabetic mice triggers early onset of diabetes and produces a wide spectrum of T cell-mediated autoimmune diseases, incl...

Hepatitis C virus (HCV) poses a global health problem because it readily establishes persistent infection and a vaccine is not available. CD4(+)CD25(+) T cells have been implicated in HCV persistence because their frequency is increased in the blood of HCV-infected patients and their in vitro depletion results in increased IFN-gamma production by HCV-specific T cells. Studying a well-characteri...

CD4(+) CD25(+) T cells are a population of regulatory T cells associated with control of arthritis in anti-interleukin-17 antibody-treated Borrelia-vaccinated and challenged gamma interferon-deficient mice. Here, we present direct evidence that adoptive transfer of enriched CD4(+) CD25(+) T cells from these mice can prevent the development of arthritis in Borrelia-vaccinated and challenged mice...

Expression of the IL-2 receptor alpha chain (CD25) by peripheral CD4 T cells follows cellular activation. However, CD25 expression by CD4 cells is widely used as a marker to identify regulatory T cells (T(R)), although cells with regulatory properties are also found in the CD4+CD25- subset. By using in vivo functional assays and Foxp3 expression as a faithful marker of T(R) differentiation, we ...