TY - JOUR
T1 - IL-33 is an unconventional alarmin that stimulates IL-2 secretion by dendritic cells to selectively expand IL-33R/ST2+ regulatory T cells
AU - Matta, Benjamin M.
AU - Lott, Jeremy M.
AU - Mathews, Lisa R.
AU - Liu, Quan
AU - Rosborough, Brian R.
AU - Blazar, Bruce R.
AU - Turnquist, Heth R.
N1 - Publisher Copyright:
Copyright © 2014 by The American Association of Immunologists, Inc.
PY - 2014/10/15
Y1 - 2014/10/15
N2 - IL-33 is a recently characterized IL-1 family member that is proposed to function as an alarmin, or endogenous signal of cellular damage, as well as act as a pleiotropic cytokine. The ability of IL-33 to potentiate both Th1 and Th2 immunity supports its role in pathogen clearance and disease immunopathology. Yet, IL-33 restrains experimental colitis and transplant rejection by expanding regulatory T cells (Treg) via an undefined mechanism. We sought to determine the influence of IL-33 on hematopoietic cells that drives Treg expansion and underlies the therapeutic benefit of IL-33 administration. In this study, we identify a feedback loop in which conventional mouse CD11c+ dendritic cells (DC) stimulated by IL-33 secrete IL-2 to selectively expand IL-33R(ST2+)-suppressive CD4+Foxp3+ Treg. Interestingly, this occurs in the absence of classical DC maturation, and DC-derived (innate) IL-2 increases ST2 expression on both DC and interacting Treg. ST2+ Treg represent an activated subset of Foxp3+ cells, demonstrated to be ICOShighCD44high compared with their ST2- counterparts. Furthermore, although studies have shown that IL-33-exposed DC promote Th2 responses, we reveal that ST2+ DC are required for IL-33-mediated in vitro and in vivo Treg expansion. Thus, we have uncovered a relationship between IL-33 and innate IL-2 that promotes the selective expansion of ST2+ Treg over non-Treg. These findings identify a novel regulatory pathway driven by IL-33 in immune cells that may be harnessed for therapeutic benefit or for robust expansion of Treg in vitro and in vivo.
AB - IL-33 is a recently characterized IL-1 family member that is proposed to function as an alarmin, or endogenous signal of cellular damage, as well as act as a pleiotropic cytokine. The ability of IL-33 to potentiate both Th1 and Th2 immunity supports its role in pathogen clearance and disease immunopathology. Yet, IL-33 restrains experimental colitis and transplant rejection by expanding regulatory T cells (Treg) via an undefined mechanism. We sought to determine the influence of IL-33 on hematopoietic cells that drives Treg expansion and underlies the therapeutic benefit of IL-33 administration. In this study, we identify a feedback loop in which conventional mouse CD11c+ dendritic cells (DC) stimulated by IL-33 secrete IL-2 to selectively expand IL-33R(ST2+)-suppressive CD4+Foxp3+ Treg. Interestingly, this occurs in the absence of classical DC maturation, and DC-derived (innate) IL-2 increases ST2 expression on both DC and interacting Treg. ST2+ Treg represent an activated subset of Foxp3+ cells, demonstrated to be ICOShighCD44high compared with their ST2- counterparts. Furthermore, although studies have shown that IL-33-exposed DC promote Th2 responses, we reveal that ST2+ DC are required for IL-33-mediated in vitro and in vivo Treg expansion. Thus, we have uncovered a relationship between IL-33 and innate IL-2 that promotes the selective expansion of ST2+ Treg over non-Treg. These findings identify a novel regulatory pathway driven by IL-33 in immune cells that may be harnessed for therapeutic benefit or for robust expansion of Treg in vitro and in vivo.
UR - http://www.scopus.com/inward/record.url?scp=84907569702&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84907569702&partnerID=8YFLogxK
U2 - 10.4049/jimmunol.1400481
DO - 10.4049/jimmunol.1400481
M3 - Article
C2 - 25217167
AN - SCOPUS:84907569702
SN - 0022-1767
VL - 193
SP - 4010
EP - 4020
JO - Journal of Immunology
JF - Journal of Immunology
IS - 8
ER -