CTLA4 (Cytotoxic T-Lymphocyte-Associated Protein 4): CTLA4 encodes a protein that is crucial for regulating immune responses by inhibiting the activation of T cells. CTLA4 competes with the co-stimulatory receptor CD28 for binding to CD80/CD86 on antigen-presenting cells. Its role is to prevent excessive T cell activation and maintain immune tolerance. Dysregulation of CTLA4 is associated with autoimmune diseases....