O'Gorman WE, Dooms H, Thorne SH, Kuswanto WF, Simonds EF, Krutzik PO, Nolan GP, Abbas AK. The initial phase of an immune response functions to activate regulatory T cells.
J Immunol 2009;
183:332-9. [PMID:
19542444 DOI:
10.4049/jimmunol.0900691]
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Abstract
An early reaction of CD4(+) T lymphocytes to Ag is the production of cytokines, notably IL-2. To detect cytokine-dependent responses, naive Ag-specific T cells were stimulated in vivo and the presence of phosphorylated STAT5 molecules was used to identify the cell populations responding to IL-2. Within hours of T cell priming, IL-2-dependent STAT5 phosphorylation occurred primarily in Foxp3(+) regulatory T cells. In contrast, the Ag-specific T cells received STAT5 signals only after repeated Ag exposure or memory differentiation. Regulatory T cells receiving IL-2 signals proliferated and developed enhanced suppressive activity. These results indicate that one of the earliest events in a T cell response is the activation of endogenous regulatory cells, potentially to prevent autoimmunity.
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