TY - JOUR
T1 - Limited tumor infiltration by activated T effector cells restricts the therapeutic activity of regulatory T cell depletion against established melanoma
AU - Quezada, Sergio A.
AU - Peggs, Karl S.
AU - Simpson, Tyler R.
AU - Shen, Yuelei
AU - Littman, Dan R.
AU - Allison, James P.
PY - 2008/9/1
Y1 - 2008/9/1
N2 - Interference with inhibitory immunological checkpoints controlling T cell activation provides new opportunities to augment cancer immunotherapies. Whereas cytotoxic T lymphocyte-associated antigen-4 blockade has shown promising preclinical and clinical results, therapeutic CD4+CD25+ T reg cell depletion has failed to consistently enhance immunebased therapies. Using B16/BL6, a transplantable murine melanoma model, we show a dichotomy between the effects of T reg cell depletion on tumor rejection dependent on whether depletion occurs before (prophylactic) or after (therapeutic) tumor engraftment. Failure to promote rejection with therapeutic depletion is not related to lack of T reg cell depletion, to elimination of CD25+ effector T cells, or to a failure to enhance systemic antitumor T cell responses, but correlates with failure of effector cells to infiltrate the tumor and increase the intratumor ratio of effector T cell/T reg cell. Finally, systemic antitumor responses generated upon therapeutic T reg cell depletion are significantly stronger than those generated in the presence of T reg cells, and are capable of eliciting rejection of established tumors after transfer into immunoablated recipients receiving combination immunotherapy. The data demonstrate a dissociation between measurable systemic responses and tumor rejection during CD25-directed T reg cell depletion, and suggest an alternative, clinically applicable strategy for the treatment of established tumors.
AB - Interference with inhibitory immunological checkpoints controlling T cell activation provides new opportunities to augment cancer immunotherapies. Whereas cytotoxic T lymphocyte-associated antigen-4 blockade has shown promising preclinical and clinical results, therapeutic CD4+CD25+ T reg cell depletion has failed to consistently enhance immunebased therapies. Using B16/BL6, a transplantable murine melanoma model, we show a dichotomy between the effects of T reg cell depletion on tumor rejection dependent on whether depletion occurs before (prophylactic) or after (therapeutic) tumor engraftment. Failure to promote rejection with therapeutic depletion is not related to lack of T reg cell depletion, to elimination of CD25+ effector T cells, or to a failure to enhance systemic antitumor T cell responses, but correlates with failure of effector cells to infiltrate the tumor and increase the intratumor ratio of effector T cell/T reg cell. Finally, systemic antitumor responses generated upon therapeutic T reg cell depletion are significantly stronger than those generated in the presence of T reg cells, and are capable of eliciting rejection of established tumors after transfer into immunoablated recipients receiving combination immunotherapy. The data demonstrate a dissociation between measurable systemic responses and tumor rejection during CD25-directed T reg cell depletion, and suggest an alternative, clinically applicable strategy for the treatment of established tumors.
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U2 - 10.1084/jem.20080099
DO - 10.1084/jem.20080099
M3 - Article
C2 - 18725522
AN - SCOPUS:51049108540
SN - 0022-1007
VL - 205
SP - 2125
EP - 2138
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
IS - 9
ER -