Formatting and gene-based delivery of a human PD-L1 single domain antibody for immune checkpoint blockade

Monoclonal antibodies that target the inhibitory immune checkpoint axis consisting of programmed cell death protein 1 (PD-1) and its ligand, PD-L1, have changed the immune-oncology field. We identified K2, an anti-human PD-L1 single-domain antibody fragment, that can enhance T cell activation and tu...

Full description

Bibliographic Details
Main Authors: Robin Maximilian Awad, Quentin Lecocq, Katty Zeven, Thomas Ertveldt, Lien De Beck, Hannelore Ceuppens, Katrijn Broos, Yannick De Vlaeminck, Cleo Goyvaerts, Magali Verdonck, Geert Raes, Alexander Van Parys, Anje Cauwels, Marleen Keyaerts, Nick Devoogdt, Karine Breckpot
Format: Article
Language:English
Published: Elsevier 2021-09-01
Series:Molecular Therapy: Methods & Clinical Development
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2329050121001017
Description
Summary:Monoclonal antibodies that target the inhibitory immune checkpoint axis consisting of programmed cell death protein 1 (PD-1) and its ligand, PD-L1, have changed the immune-oncology field. We identified K2, an anti-human PD-L1 single-domain antibody fragment, that can enhance T cell activation and tumor cell killing. In this study, the potential of different K2 formats as immune checkpoint blocking medicines was evaluated using a gene-based delivery approach. We showed that 2K2 and 3K2, a bivalent and trivalent K2 format generated using a 12 GS (glycine-serine) linker, were 313- and 135-fold more potent in enhancing T cell receptor (TCR) signaling in PD-1POS cells than was monovalent K2. We further showed that bivalent constructs generated using a 30 GS linker or disulfide bond were 169- and 35-fold less potent in enhancing TCR signaling than was 2K2. 2K2 enhanced tumor cell killing in a 3D melanoma model, albeit to a lesser extent than avelumab. Therefore, an immunoglobulin (Ig)G1 antibody-like fusion protein was generated, referred to as K2-Fc. K2-Fc was significantly better than avelumab in enhancing tumor cell killing in the 3D melanoma model. Overall, this study describes K2-based immune checkpoint medicines, and it highlights the benefit of an IgG1 Fc fusion to K2 that gains bivalency, effector functions, and efficacy.
ISSN:2329-0501