Limited tumor infiltration by activated T effector cells restricts the therapeutic activity of regulatory T cell depletion against established melanoma.

ABSTRACT: 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 immune-based 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 antitumo

SUBMITTER: Quezada SA 

PROVIDER: S-EPMC2526206 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature