TY - JOUR
T1 - Interleukin-7 restores immunity in athymic T-cell-depleted hosts
AU - Fry, Terry J.
AU - Christensen, Barbara L.
AU - Komschlies, Kristin L.
AU - Gress, Ronald E.
AU - Mackall, Crystal L.
PY - 2001/3/15
Y1 - 2001/3/15
N2 - Thymic-deficient hosts rely primarily on antigen-driven expansion to restore the peripheral T-cell compartment following T-cell depletion (TCD). The degree to which this thymic-independent pathway can restore immune competence remains poorly understood but has important implications for a number of clinical conditions including stem cell transplantation and human immunodeficiency virus (HIV) infection. A model of HY-mediated skin graft rejection by athymic, TCD mice was used to show that restoration of naive and recall responses via peripheral expansion requires transfer of only 25 × 106 lymph node (LN) cells representing approximately 10% of the T-cell repertoire. Consitutive expression of bcl-2 in the expanding inocula restored recall responses to HY at a substantially lower LN cell dose (1 × 106), which is normally insufficient to induce HY-mediated graft rejection in athymic hosts. Interestingly, bcl-2 had no effect on primary responses. Interleukin-7 (IL-7) potently enhanced thymic-independent peripheral expansion and led to HY graft rejection using an LN cell dose of 1 × 106 in both primary and recall models. The restoration of immune competence by IL-7 appeared to be mediated through a combination of programmed cell death inhibition, improved costimulation, and modulation of antigen-presenting cell (APC) function. These results show that immune competence for even stringent antigens such as HY can be restored in the absence of thymic function and identify IL-7 as a potent modulator of thymic-independent T-cell regeneration.
AB - Thymic-deficient hosts rely primarily on antigen-driven expansion to restore the peripheral T-cell compartment following T-cell depletion (TCD). The degree to which this thymic-independent pathway can restore immune competence remains poorly understood but has important implications for a number of clinical conditions including stem cell transplantation and human immunodeficiency virus (HIV) infection. A model of HY-mediated skin graft rejection by athymic, TCD mice was used to show that restoration of naive and recall responses via peripheral expansion requires transfer of only 25 × 106 lymph node (LN) cells representing approximately 10% of the T-cell repertoire. Consitutive expression of bcl-2 in the expanding inocula restored recall responses to HY at a substantially lower LN cell dose (1 × 106), which is normally insufficient to induce HY-mediated graft rejection in athymic hosts. Interestingly, bcl-2 had no effect on primary responses. Interleukin-7 (IL-7) potently enhanced thymic-independent peripheral expansion and led to HY graft rejection using an LN cell dose of 1 × 106 in both primary and recall models. The restoration of immune competence by IL-7 appeared to be mediated through a combination of programmed cell death inhibition, improved costimulation, and modulation of antigen-presenting cell (APC) function. These results show that immune competence for even stringent antigens such as HY can be restored in the absence of thymic function and identify IL-7 as a potent modulator of thymic-independent T-cell regeneration.
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U2 - 10.1182/blood.V97.6.1525
DO - 10.1182/blood.V97.6.1525
M3 - Article
C2 - 11238086
AN - SCOPUS:0035869394
SN - 0006-4971
VL - 97
SP - 1525
EP - 1533
JO - Blood
JF - Blood
IS - 6
ER -