PD-1 silencing was confirmed in parallel at both the mRNA and protein level (Supplementary Figure S2) (In contrast, PH-762 did not elicit significant release of cytokine release syndrome (CRS) associated cytokines IL-2, IL-6, IL-10, TNF-α, or IFN-γ from unstimulated human PBMCs derived from ten individual donors (Supplementary Figure S3) suggesting that functional effects of PH-762 are confined to activated T cells (that express PD-1), such as those that have been TCR-stimulated. This evidence concerns the gene IL10 and congenital rubella syndrome.