The role of regulatory T cells in the modulation of anti-tumor immune response

Abstract

It has been shown that the loss of regulatory function by deple­ + Regulatory T cells (Treg) represent a subset of CD4 T cells whose function is to suppress immune responses. Treg lymphocytes can be divided into two subsets: natural nTreg lymphocytes that are developed in the thymus and inducible iTreg lymphocytes, which originate from conventional T lymphocytes on the periphery. The majority of Treg lymphocytes express high levels of interleukin­2 (IL­2) receptor α chain (CD25) and transcription factor FoxP3 (critical for the development and suppressor activity of iTreg lymphocytes). Cancer cells can modulate anti­tumor immune response indirectly, through the activation of Treg lymphocytes. tion of tumor­induced Treg lymphocytes may enhance effectors response, resulting in tumor rejection, while the increased number of Treg lymphocytes effectively prevents tumor destruction. nTreg lymphocytes express increasingly CTLA­4 and membrane­ bound TGF­β, which inhibits cytokine production and responses of effectors lymphocytes. iTreg lymphocytes secrete immunosuppressive cytokines such as IL­10 and TGF­β. Treg lymphocytes represent one of important obstruction in anti­tumor immunity.

Keywords

• regulatory T cells
• tumors
• anti­tumor immune response