Aptamers Targeting the PD-1/PD-L1 Axis: A Perspective

Aptamers have emerged in recent years as alternatives to antibodies or small molecules to interfere with the immune check points by blocking the PD-1/PD-L1 interactions and represent an interesting perspective for immuno-oncology. Aptamers are RNA or DNA nucleotides able to bind to a target with high affinity, with the target ranging from small molecules to proteins and up to cells. Aptamers are identified by the SELEX method that can be modified for specific purposes. The range of applications of aptamers covers therapy as well as new alternative assay technologies similar to ELISA. Aptamers' limited plasma stability can be managed using delivery strategies. The goal of this Perspective is to give an overview of the current development of aptamers targeting the most studied immune checkpoint modulators, PD-1 and PD-L1, and analogous strategies with aptamers for other immuno-related targets.