ICOS/ICOSL signalling leads to the activation, proliferation and survival of cytotoxic T cells, as well as the survival of memory T cells.
ICOS [CD278] – ICOSL [CD275] Pathway
![ICOS [CD278] – ICOSL [CD275] Pathway](https://www.caltagmedsystems.co.uk/information/wp-content/uploads/icos-600x400px-600x300.png "ICOS [CD278] – ICOSL [CD275] Pathway")
PD-1 [CD279]/PD-L1 [CD274] Pathway
![PD-1 [CD279]/PD-L1 [CD274] Pathway](https://www.caltagmedsystems.co.uk/information/wp-content/uploads/pd-1-600x400px-600x300.png "PD-1 [CD279]/PD-L1 [CD274] Pathway")
The PD-1/PD-L1 or PD-L2 signalling pathway is a negative regulatory mechanism that inhibits T cell proliferation and cytokine production.