Fig. 1
From: A lesion-selective albumin-CTLA4Ig as a safe and effective treatment for collagen-induced arthritis
The strategy to develop a lesion-selective Alb-CTLA-4Ig for the treatment of collagen-induced arthritis. A Albumin is linked (via a hinge sequence) to the N-terminus of CTLA4Ig to mask its binding sites to CD80. Albumin can be removed by MMP digestion at the hinge sequence to restore the binding activity. B When Alb-CTLA4Ig circulates through normal tissues (left), it is inactive due to the low expression of MMPs. However, Alb-CTLA4Ig is converted to an active form (CTLA4Ig) when it enters the inflammatory tissues where MMPs are selectively overexpressed. The activated form can bind to CD80 or CD86 to block the second signal required for full T cell activation.