effector T cell exhausted T cell Exhausted T cells, or T cell exhaustion, represent a state of T lymphocytes characterized by diminished responses to antigenic stimulation and reduced proliferative immunity. Following prolonged exposure to antigens, such as in chronic viral infections or cancer, T cell exhaustion is a progressive loss of function that can lead to severe impairment of the immune response, potentially resulting in the deletion of the T cell population. A key feature of exhausted T cells involves the persistent coexpression of several inhibitory surface receptors commonly known as immune checkpoints. These checkpoints play a crucial role in regulating T-cell activity, allowing for the controlled suppression of immune responses following activation. Unlike effector or memory T cells that take part vigorously in the elimination of pathogenic agents and provide long-term immunity respectively, exhausted T cells express a range of inhibitory receptors, which dampen the immune response. Though intended to prevent immunopathology that might arise from uncontrolled T cell activation, this immune-suppressive function often plays into the hands of chronic viral infections and tumors, preventing the effective clearance of pathogens and malignant cells. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) An effector T cell that displays impaired effector functions (e.g., rapid production of effector cytokines, cytotoxicity) and has limited proliferative potential. https://cellxgene.cziscience.com/cellguide/CL_0011025 Tex cell