Fig. 4.

Specificity and affinity of P2c2s and P34. (A) Selective binding of indicated aptamers to recombinant human PD1 (hPD1, residues 21–168, C-terminal His-tag) and to recombinant mouse PD1 (mPD1, residues 25–167, C-terminal His-tag) as determined using ELISA. cNEG1 and cNEG2 – non-specific controls. (B) Representative SPR sensograms characterizing binding of tested aptamers to immobilized PD1. (C) Target protein binding by aptamers immobilized on magnetic beads as analyzed by SDS-PAGE. (D) Specificity of P2c2s and P34. The affinity of tested aptamers to a set of proteins as determined by ELISA.