Authors: Rebecca J. Boohaker, Vijaya Sambandam, Isaac Segura, James Miller, Mark Suto, Bo Xu
Source: journals.elsevier.com
Received February 10, 2018. Received in revised form April 13, 2018. Accepted April 22, 2018
Synopsis: We report here the rational design and validation of a peptide inhibitor to the PD-1/PD-L1 interaction as an attempt to develop a viable alternative to current inhibitory antibodies. We demonstrated, by biolayer interferometry and in silico docking simulations, that a PD-L1 peptide mimetic (PL120131) can interfere with the PD-1/PD-L1 interaction by binding to PD-1. We show that PL120131 is capable of inhibiting PD-1 mediated apoptotic signaling pathway and rescuing Jurkat cells and primary lymphocytes from apoptosis. Additionally, we show that PL120131 treatment allows for CTL anti-tumor activity. Furthermore, PL120131 can maintain co-culture survivability and activity of T Cells in a 3D co-culture model better than the anti-PD-1 blocking antibody. Together, the characterization of this PD-1/PD-L1 inhibiting peptide provides insight regarding the ability to inhibit PD-L1 binding while maintaining CTL viability and activity that can further the development of alternatives to antibody based immunotherapies.