RE: Notice9 Jun 2019 12:17
PD1 shows up everywhere in the immune system ... which is why Keytruda and checkpoints have toxicity ..
take vascular decease ............
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457250/
PD-1 is exclusively expressed on activated immune cells, most importantly on T cells, thus exclusively regulating ongoing immune responses, both in secondary lymphoid organs and in peripheral tissue sites. Engagement of PD-1 by its ligand PD-L1 (B7-H1, CD274) downregulates TCR and CD28-mediated activation cascades. PD-1 inhibits signaling pathways involved in glucose metabolism and cell cycle regulation, including the PI3K–Akt–mTOR and Ras–MEK–ERK pathways, thus impacting critical survival functions in normal tissues [16–18]. PD-L1 is expressed on antigen-presenting cells (dendritic cells, macrophages etc) and on endothelial cells (EC). In animal studies, the PD-1 immune checkpoint has been implicated in protecting tissue tolerance and disruption of PD-1 and PD-L1-associated negative signaling has been associated with inflammatory disease [19–21]. Remarkably, PD-L1 is often abundantly expressed in cancer cells, and has been implicated in the immune evasion strategy of malignant cells, that paralyze anti-tumor T cells by engaging their PD-1 receptors. Accordingly, therapeutic blockade of PD-1 or PD-L1 in cancer patients has heralded in a revolution in cancer immunotherapy.