Fig. 3.

Conditioned Media AlphaScreen for high sensitivity elucidation of immune receptor interactomes. Recombinant PD-1 and CD86 proteins were biotinylated and analyzed for binding to the library of STM receptors following the experimental procedure described in the text. S/N ratio ≥ 20 was determined as experimentally-validated cut-off for hit calling (dotted gray line). A, PD-1 screens using the Conditioned Media AlphaScreen platform identify PD-L1 and PD-L2 and B, CD86 screening using the Conditioned Media AlphaScreen workflow allows identification of the binding partners CTLA4 and CD28 as top scoring hits. Hits labeled in gray color have been empirically determined to be nonspecific binders.