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Updated: Jul 17, 2026

Human In Vitro Suppression as Screening Tool for the Recognition of an Early State of Immune Imbalance
Published on: July 22, 2011
CpG DNA inhibits CD4+CD25+ Treg suppression through direct MyD88-dependent costimulation of effector CD4+ T cells
David F LaRosa1, Andrew E Gelman, Adeeb H Rahman
1Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Toll-like receptor (TLR) ligands are notable for their ability to induce APC maturation, which in turn facilitates optimal T cell mediated immune responses. Toll-like receptor ligands, such as CpG DNA, can also modulate immune responses by blocking the suppressive effects of CD4+CD25+ regulatory T cells (Tregs). Recently, we have demonstrated that CpG DNA, in addition to its actions on APCs and Tregs, can provide direct costimulatory signals to CD4+CD25- T cells. Here we show that this costimulatory effect is sufficient to abrogate suppression by Tregs. These data indicate a previously undefined role for TLR ligands in directly modulating CD4+ T cell responses.
Toll-like receptor (TLR) ligands are notable for their ability to induce APC maturation, which in turn facilitates optimal T cell mediated immune responses. Toll-like receptor ligands, such as CpG DNA, can also modulate immune responses by blocking the suppressive effects of CD4+CD25+ regulatory T cells (Tregs). Recently, we have demonstrated that CpG DNA, in addition to its actions on APCs and Tregs, can provide direct costimulatory signals to CD4+CD25- T cells. Here we show that this costimulatory effect is sufficient to abrogate suppression by Tregs. These data indicate a previously undefined role for TLR ligands in directly modulating CD4+ T cell responses.
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