Programmed Death Ligand 2 in Cancer-Induced Immune Suppression

Figure 1

PD-L2/PD-1 signaling. PD-L2 expression by different cell types is regulated by STAT6 and NF-κB, although other possible regulators cannot be excluded. The most potent inducers of PD-L2 expression appear to be Th2 cytokines, particularly IL-4. Several new activators of STAT6 (such as viruses) have been found, but whether they therefore also upregulate PD-L2 is not known yet. PD-L2/PD-1 interaction results in the suppression of TCR-induced PI3K/AKT activation and subsequent attenuation of T cell survival, cytokine production and proliferation.