Fig. 1
From: Severe toxicity from checkpoint protein inhibitors: What intensive care physicians need to know?
Checkpoint inhibitors: mode of action. a Tumor cell inhibition of the immune system: tumor cells decrease T cell activation via two pathways. Within the tumor, connection between tumor cell PDL-1 and T cell receptor PD-1 associated with MHC T cell receptor leads to inhibition of T cell function. Within the lymphoid tissue, tumor cells inhibit dendritic cells via the CTLA-4 pathway. Cancer cells increase CTLA4 expression by dendritic cells, through T reg cell stimulation. Interaction of CTLA4-Receptor on T cell, inhibits T cell function [1]. b Mode of action of CTLA-4i or PD-1/PDL-1i. PD-1/PDL-1i blocks the connection between PD-1 and PDL-1 and prevents the inhibition of T cells. T cell cytotoxicity then attacks the tumor cells. CTLA-4i blocks the connection between dendritic cells and T cells related to CTL14. CTLA-4i removes the inhibition related to dendritic cell on T cells