Immune checkpoint proteins (ICPs)

Immune checkpoint proteins are a diverse group of cell surface molecules that regulate the timing and intensity of immune responses to maintain self-tolerance and prevent collateral tissue damage. In the context of oncology, tumors often exploit inhibitory checkpoint pathways, such as the Programmed Cell Death 1 (PD-1) or Cytotoxic T-Lymphocyte Associated Protein 4 (CTLA-4) axes, to suppress T-cell activity and evade immune surveillance (National Cancer Institute, 2023). Therapeutic modulators, primarily monoclonal antibodies, are designed to inhibit these 'brakes' on the immune system, thereby re-activating cytotoxic T-cells to recognize and destroy malignant cells (StatPearls, 2023). While these therapies have revolutionized cancer treatment, they are frequently associated with immune-related adverse events (irAEs) due to the systemic loss of immune checkpoints that protect healthy tissues (Nature Reviews Drug Discovery, 2020). The field is currently expanding to include next-generation targets such as LAG-3, TIM-3, and TIGIT to overcome resistance to first-generation inhibitors (PubMed, PMC7139891). This entry is marked as incorrect/broad because 'Immune checkpoint modulators' refers to a therapeutic class rather than a specific singular molecular target.

Other names

Immune checkpointsImmune checkpoint receptorsCo-inhibitory receptorsCo-stimulatory receptorsNegative immune regulators

Immune checkpoint modulators function by blocking inhibitory signaling pathways (e.g., PD-1/PD-L1 or CTLA-4) that tumors use to evade the immune system. By binding to these receptors or their ligands, the drugs prevent the 'off' signal to T-cells, thereby restoring and enhancing the anti-tumor immune response. Conversely, some modulators may target co-stimulatory pathways to amplify immune activity.