Research on the Mechanism and Clinical Application of CTLA-4 in Tumor Immunotherapy

Immune checkpoint inhibitors, as an important therapeutic approach, are playing an increasingly important role in current cancer treatment, providing newer and better options compared to traditional tumor treatment regimens. Clarifying its mechanism of action and clinical application is the key to improving therapeutic effect and prognosis. Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) plays a key role in regulating the proliferation and activation of T cells. The CTLA-4 molecule competitively binds to the B7 molecule with CD28, affecting the kinetics of T-cell responses. In regulatory T cells (Tregs), the stimulation of T-cell receptor (TCR) up-regulates the expression of CTLA-4 to inhibit antigen-presenting cells (APCs). The review will summarize the molecular mechanism and immunosuppressive mechanism of CTLA-4 immune regulation, as well as the research and development and clinical application of CTLA-4 inhibitors.