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Updated: Jul 19, 2026

Human In Vitro Suppression as Screening Tool for the Recognition of an Early State of Immune Imbalance
Published on: July 22, 2011
Competition controls the rate of transition between the peripheral pools of CD4+CD25- and CD4+CD25+ T cells
Afonso R M Almeida1, Bruno Zaragoza, Antonio A Freitas
1Lymphocyte Population Biology Unit, URA CNRS 1961, Institut Pasteur, 28 Rue du Dr. Roux, 75015 Paris, France.
Abstract:
Recent reports have hinted that it is possible to regenerate CD4+CD25+ regulatory T cells (Treg) from CD4+CD25- cells, a phenomenon termed conversion. We evaluated the relative contribution of this process to the Treg pool by transferring purified populations of CD4+ T cells into T cell-deficient mice. We report that conversion of CD25- cells into the CD4+CD25+Treg pool is minor if other bona fide CD25+ Tregs are present. Moreover, in the same hosts, the loss of CD25 expression by a population of Tregs also decreases in the presence of co-injected CD4+CD25- cells. Thus, the rate of exchange between CD25- and CD25+ T-cell populations is determined by the presence or absence of T-cell competitors. Our results attest for the role of competition in the contribution of different T-cell subsets for the regeneration of the peripheral CD4+ T-cell pool during lymphopenia.
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