FIGURE 2.

Deactivated (A) and activated (B) T cell-based on immune checkpoint inhibitors mechanism. During resting of T cell (deactivated T cell), CTLA4 and PD1 receptors on T cell surface binds to CD80 and CD86 on the antigen-presenting cell (APC) such as dendritic cell and PDL-1 and PDL-2 on cancer cell, respectively, while T cell receptor (TCR) binds to major histocompatibility complex (MHC) with the presence of peptide. Thus, no immune response triggered to kill cancer cells. T cells will only be activated with the presence of blockade or inhibitor on CTLA4 and PD1 receptors. Hence, a CTLA4 inhibitor known as Ipilimumab and PD1 inhibitor of Nivolumab functioned to block those receptors and elicit immune response thus leading to the apoptosis of cancer cells.