Regulatory T cells specifically suppress conventional CD8 alpha beta T cells in intestinal tumors of APC(Min/+) mice

• The presence of activated T cells in colorectal cancer tissues is a strong predictor of patient survival. Our previous studies have shown that regulatory T cells (Treg) are able to reduce T cell transendothelial migration in vitro and accumulation of effector T cells in intestinal tumors in vivo in the murine APC(Min/+) model for microsatellite stable intestinal tumors. In this study, we investigated the effect of Treg depletion on the density and effector functions of different TCR alpha beta(+) and TCR gamma delta(+) T cell populations in intestinal tumors. We used the APC(Min/+)\DEREG mouse model, which harbor a diphtheria toxin receptor under the control of the FOXP3 promoter, to deplete Treg in tumor bearing mice. We found that the density of conventional TCR alpha beta(+)CD8 alpha beta(+) T cells was significantly increased in Treg-depleted tumors in comparison with Treg-proficient tumors. Furthermore, TCR alpha beta(+)CD8 alpha beta(+) T cells showed increased proliferation and activation as well as increased Granzyme B and IFN-gamma production in Treg-depleted tumors. In sharp contrast, the densities and effector functions of TCR alpha beta(+)CD8 alpha alpha(+) T cells and TCR gamma delta(+) T cells remained unchanged by Treg depletion. We also documented a distinct population of IL-17A(+)TNF(+) TCR gamma delta(+)CD8(-) T cells in tumors, which were not affected by Treg depletion. We conclude that Treg depletion affects only conventional TCR alpha beta(+)CD8 alpha beta(+) T cells in intestinal tumors, while unconventional T cells and T cells in unaffected tissue are not altered. Immunotherapies aimed at depleting Treg from tumors may thus be a viable option for reinvigoration of conventional cytotoxic T cells with a Th1 cytokine profile.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Microbiology in the medical area (hsv//eng)

Nyckelord

Regulatory T cells

APCmin

Colon cancer

Tumor-infiltrating

lymphocytes

Anti-tumor immunity

chemokine production

colon-cancer

accumulation

promote

gamma

angiogenesis

mechanisms

landscape

depletion

responses

Oncology

Immunology

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)