Immune tolerance

Immune tolerance is a fundamental immunological state characterized by the active non-responsiveness of the immune system to specific antigens, particularly self-antigens, to prevent autoimmunity (StatPearls, 2023). It is broadly divided into central tolerance, which occurs during the early stages of lymphocyte development in primary lymphoid organs like the thymus and bone marrow, and peripheral tolerance, which is maintained by mature lymphocytes in the circulation and peripheral tissues (NIH, 2022). Mechanisms underlying this process include clonal deletion, anergy, and the suppressive activity of regulatory T cells (Tregs) (Nature Reviews Immunology, 2020). In clinical practice, the induction of immune tolerance is a primary goal in treating autoimmune disorders and preventing the rejection of transplanted organs. Conversely, in oncology, breaking immune tolerance is a key strategy to enable the immune system to recognize and eliminate malignant cells that have co-opted these pathways for immune evasion (PubMed, 2021). Because it represents a complex physiological state involving multiple cell types and signaling pathways rather than a single protein, it is classified as a biological process rather than a discrete molecular target.

Other names

Immunological toleranceSelf-tolerancePeripheral toleranceCentral toleranceImmune unresponsiveness

Modulation of immune checkpoints, induction of regulatory T cells, inhibition of co-stimulatory signals, or antigen-specific desensitization.