Cbl-b

Notes

original target text: Cbl-b inhibitor

Cbl-b (Casitas B-lineage lymphoma proto-oncogene b) is an intracellular enzyme belonging to a family of E3 ubiquitin ligases, proteins that mark other proteins for degradation or functional modification by attaching a small protein tag called ubiquitin. In immune cells, especially T lymphocytes and natural killer cells, Cbl-b acts as a brake on activation: it dampens signaling that begins when a T-cell receptor recognizes an antigen, helping to prevent excessive or misdirected immune responses and maintaining tolerance to the body's own tissues. Because tumors often exploit inhibitory circuits like this one to evade immune attack, blocking Cbl-b is being explored as a way to lower the activation threshold of T cells and natural killer cells, encouraging a more vigorous anti-tumor immune response. This places Cbl-b inhibition conceptually alongside other immune checkpoint strategies, though it works inside the cell rather than at the cell surface. The approach is relevant chiefly in oncology, where restoring or amplifying immune recognition of malignant cells is a central therapeutic goal. Because Cbl-b also contributes to preventing autoimmunity, modulating it carries an inherent trade-off between enhancing anti-tumor immunity and the risk of unwanted immune activation against normal tissue.