T cell exhaustion is a state of T cell dysfunction in chronic infection and tumor. Main characteristics of exhausted T cell (Tex) are progressive loss of effector function, sustained and high expression of inhibitory receptors, changes in the expression of transcription factors and metabolism dysregulation. According to these characteristics, Tex can be distinguished from effector T cells and memory T cells. Weak control of infection and tumor by Tex leads to chronic persistent infection and tumor occurrence. Tex is not irreversible. Targeting immunoregulatory targets can effectively reverse Tex, and restore anti-tumor immune response and improve tumor control rate. Therefore, reversing Tex may be one of the new ways of tumor immunotherapy. This article discusses influencing factors of T cell exhaustion, cell functional characteristics of Tex and its application in clinical treatment, in order to provide a new idea for tumor immunotherapy by reversing the state of Tex.
