Cytotoxic T-lymphocyte-associated antigen 4–immunoglobulin fusion protein (Abatacept (CTLA-4-Ig))

Abatacept is a recombinant fusion protein consisting of the extracellular domain of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) linked to the Fc fragment of human IgG1[1]. It selectively inhibits T-cell activation by binding to CD80 and CD86 on antigen-presenting cells, thereby blocking the necessary co-stimulatory signal for T-cell proliferation. This mechanism reduces abnormal immune responses and inflammation associated with autoimmune diseases. It is approved for use in adults and children for conditions such as rheumatoid arthritis, psoriatic arthritis, polyarticular juvenile idiopathic arthritis, and as prophylaxis for acute graft-versus-host disease in stem cell transplant patients[1][5][7]. Abatacept is typically administered intravenously or subcutaneously and is usually considered after inadequate response to conventional DMARDs[2][3][7].

Other names

OrenciaCTLA4-IgCTLA-4 immunoglobulin fusion proteinAbatacept fusion protein

Blocks the CD80/CD86–CD28 co-stimulatory signal between antigen-presenting cells and T-cells, preventing full T-cell activation and proliferation[1][5][7]