Abstract Successful initiation of the B-cell receptor (BCR) signaling, and subsequent antigen-encounter in germinal centers are both marked by sharp increases CD25 surface-expression. Likewise, oncogenic signaling leukemia (B-ALL) lymphoma induces CD25-surface expression. While is known as an IL2-receptor chain on T- NK-cells, significance its expression B-cells was unclear. We discovered that,...

background:   brucellosis is one of the most common chronic diseases, with widespread distribution. in spite of cell-mediated immunity (cmi) modulated mainly via activated t-helper type 1 (th1) cells, brucellosis can advance to chronic disease in about 10-30% of cases. regulatory t cells (treg cells) are involved the immune response to brucellosis; however, their role, particularly in the chang...

An important pathway for immune tolerance is provided by thymic-derived CD25+ CD4+ T cells that suppress other CD25- autoimmune disease-inducing T cells. The antigen-presenting cell (APC) requirements for the control of CD25+ CD4+ suppressor T cells remain to be identified, hampering their study in experimental and clinical situations. CD25+ CD4+ T cells are classically anergic, unable to proli...

Thymic derived naturally occurring CD25+ CD4+ T regulatory cells (Tregs) suppress immune responses, including transplantation. Here we discuss the capacity of dendritic cells (DCs) to expand antigen-specific Tregs, particularly polyclonal Tregs directed to alloantigens. Initial studies have shown that mature DCs are specialized antigen-presenting cells (APCs) for expanding antigen-specific CD25...

Despite intense recent interest, the suppressive mechanisms of regulatory CD25+CD4 T cells remain poorly understood. One deficiency in the field is the lack of in vivo models where the effects of regulatory CD25+CD4 T cells on antigen-specific responder T cells can be measured quantitatively. We describe one such model here. We compared responses of adoptively transferred naive wild-type antige...

Although CD4+CD25+ regulatory T cells are pivotal in the prevention of autoimmunity and appear to mediate transplantation tolerance, little is known concerning their antigen specificity. Here we describe the induction of a human CD4+CD25+ regulatory T-cell line specific for a defined peptide alloantigen (human leukocyte antigen A2 [HLA-A2] 138-170) by priming purified CD4+CD25+ cells ex vivo. T...

BACKGROUND Upon antigen exposure, cord blood derived T cells respond to ubiquitous environmental antigens by high proliferation. To date it remains unclear whether these "excessive" responses relate to different regulatory properties of the putative T regulatory cell (Treg) compartment or even expansion of the Treg compartment itself. METHODS Cord blood (>37 week of gestation) and peripheral ...

cells produce and release granzyme B similarly to CD8 T cells, an activity not found in CD4 CD25 T cells. The authors further demonstrate that Bcell apoptosis mediated by CD4 CD25 T cells can be antigen dependent. CD4 CD25 T cells from mice bearing a transgenic TCR that recognizes an ovalbumin peptide were used for these experiments. Proliferating B cells were divided into 2 separate groups, on...

Naturally arising CD25(+)CD4(+) regulatory T (T(R)) cells can be exploited to establish immunologic tolerance to non-self antigens. In vivo exposure of CD25(+)CD4(+) T cells from normal naive mice to alloantigen in a T cell-deficient environment elicited spontaneous expansion of alloantigen-specific CD25(+)CD4(+) T(R) cells, which suppressed allograft rejection mediated by subsequently transfer...