TY - JOUR
T1 - Microbial infection-induced expansion of effector T cells overcomes the suppressive effects of regulatory T cells via an IL-2 deprivation mechanism
AU - Benson, Alicia
AU - Murray, Sean
AU - Divakar, Prashanthi
AU - Burnaevskiy, Nikolay
AU - Pifer, Reed
AU - Forman, James
AU - Yarovinsky, Felix
PY - 2012/1/15
Y1 - 2012/1/15
N2 - Foxp3 + regulatory T (Treg) cells are a critical cell population that suppresses T cell activation in response to microbial and viral pathogens. We identify a cell-intrinsic mechanism by which effector CD4 + T cells overcome the suppressive effects of Treg cells in the context of three distinct infections: Toxoplasma gondii, Listeria monocytogenes, and vaccinia virus. The acute responses to the parasitic, bacterial, and viral pathogens resulted in a transient reduction in frequency and absolute number of Treg cells. The infection-induced partial loss of Treg cells was essential for the initiation of potent Th1 responses and host protection against the pathogens. The observed disappearance of Treg cells was a result of insufficiency in IL-2 caused by the expansion of pathogen-specific CD4 + T cells with a limited capacity of IL-2 production. Exogenous IL-2 treatment during the parasitic, bacterial, and viral infections completely prevented the loss of Treg cells, but restoration of Treg cells resulted in a greatly enhanced susceptibility to the pathogens. These results demonstrate that the transient reduction in Treg cells induced by pathogens via IL-2 deprivation is essential for optimal T cell responses and host resistance to microbial and viral pathogens.
AB - Foxp3 + regulatory T (Treg) cells are a critical cell population that suppresses T cell activation in response to microbial and viral pathogens. We identify a cell-intrinsic mechanism by which effector CD4 + T cells overcome the suppressive effects of Treg cells in the context of three distinct infections: Toxoplasma gondii, Listeria monocytogenes, and vaccinia virus. The acute responses to the parasitic, bacterial, and viral pathogens resulted in a transient reduction in frequency and absolute number of Treg cells. The infection-induced partial loss of Treg cells was essential for the initiation of potent Th1 responses and host protection against the pathogens. The observed disappearance of Treg cells was a result of insufficiency in IL-2 caused by the expansion of pathogen-specific CD4 + T cells with a limited capacity of IL-2 production. Exogenous IL-2 treatment during the parasitic, bacterial, and viral infections completely prevented the loss of Treg cells, but restoration of Treg cells resulted in a greatly enhanced susceptibility to the pathogens. These results demonstrate that the transient reduction in Treg cells induced by pathogens via IL-2 deprivation is essential for optimal T cell responses and host resistance to microbial and viral pathogens.
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U2 - 10.4049/jimmunol.1100769
DO - 10.4049/jimmunol.1100769
M3 - Article
C2 - 22147768
AN - SCOPUS:84856022105
SN - 0022-1767
VL - 188
SP - 800
EP - 810
JO - Journal of Immunology
JF - Journal of Immunology
IS - 2
ER -