A PD1‐CD137L Fusion Protein More Potently Enhances Anti‐Tumour Immune Responses Than Targeting PD‐L1 and CD137 Separately
7 affiliations
- 1Department of Physiology Yong Loo Lin School of Medicine, National University of Singapore Singapore Singapore
- 2NUS Immunology Programme Life Sciences Institute, National University of Singapore Singapore Singapore
- 3NUSMED Immunology Translational Research Programme National University of Singapore Singapore Singapore
- 4Integrative Sciences and Engineering Programme National University of Singapore Singapore Singapore
- 5Department of Microbiology and Immunology Yong Loo Lin School of Medicine, National University of Singapore Singapore Singapore
- 6Department of Pharmacy, Faculty of Science National University of Singapore Singapore Singapore
- 7Department of Otorhinolaryngology‐Head and Neck Surgery Singapore General Hospital Singapore Singapore
Abstract
Tumour immune evasion frequently involves PD‐L1‐mediated inhibition of T cell activity, limiting the efficacy of PD1/PD‐L1 blockade, particularly in PD‐L1‐low or immunologically ‘cold’ tumours. To overcome this limitation, we developed a dual targeting human PD1‐CD137L (hPD1‐CD137L) fusion protein that blocks PD‐L1–PD1 inhibitory signalling and simultaneously delivers CD137‐mediated T cell costimulation. The fusion protein was produced with high purity and demonstrated specific binding to PD‐L1‐expressing tumour cells and CD137‐positive T cells. The hPD1‐CD137L retained a stable multimeric structure under acidic conditions and during prolonged storage, supporting its suitability for systemic administration and activity within the tumour microenvironment. Functionally, hPD1‐CD137L enhanced T cell activation, as evidenced by increased NF‐κB signalling and activation marker expression, and promoted robust tumour cell cytolysis in both 2D and 3D co‐culture systems. Anti‐tumour activity was observed across multiple tumour models with varying PD‐L1 expression, including nasopharyngeal carcinoma (NPC), rhabdomyosarcoma, lung carcinoma and patient‐derived colorectal cancer organoids. Notably, hPD1‐CD137L enhanced cytolysis of C666 NPC cells by patient‐derived tumour‐infiltrating lymphocytes at low effector‐to‐target ratios, and was more potent than a combination of an anti‐PD‐1 antibody and a CD137 agonist. In vivo, PBMC‐humanised NSG mice tolerated hPD1‐CD137L without significant weight loss, systemic inflammation or survival impact. Subsequent efficacy study in PBMC‐humanised, Rd18 rhabdomyosarcoma‐engrafted or C666 nasopharyngeal carcinoma‐engrafted NSG mice showed tumour growth suppression without overt toxicity. This study validates a human PD1‐CD137L fusion protein as a potent drug candidate for cancer immunotherapy.
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BibTeX
@article{xia2026pd1cd137l,
title = {{A PD1‐CD137L Fusion Protein More Potently Enhances Anti‐Tumour Immune Responses Than Targeting PD‐L1 and CD137 Separately}},
author = {Runze Xia and Emily Pauline Nickles and Yu Mei and Thamizhanban Manoharan and Yi Tian Png and Beijia Liu and Rui Sun and Kang Yi Lee and Gloryn Chia and Chwee Ming Lim and Herbert Schwarz},
journal = {Immunology},
year = {2026},
month = aug,
doi = {10.1111/imm.70189},
url = {https://doi.org/10.1111/imm.70189},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A PD1‐CD137L Fusion Protein More Potently Enhances Anti‐Tumour Immune Responses Than Targeting PD‐L1 and CD137 Separately
AU - Runze Xia
AU - Emily Pauline Nickles
AU - Yu Mei
AU - Thamizhanban Manoharan
AU - Yi Tian Png
AU - Beijia Liu
AU - Rui Sun
AU - Kang Yi Lee
AU - Gloryn Chia
AU - Chwee Ming Lim
AU - Herbert Schwarz
PY - 2026
DA - 2026/08/10
JO - Immunology
DO - 10.1111/imm.70189
UR - https://doi.org/10.1111/imm.70189
AB - Tumour immune evasion frequently involves PD‐L1‐mediated inhibition of T cell activity, limiting the efficacy of PD1/PD‐L1 blockade, particularly in PD‐L1‐low or immunologically ‘cold’ tumours. To overcome this limitation, we developed a dual targeting human PD1‐CD137L (hPD1‐CD137L) fusion protein that blocks PD‐L1–PD1 inhibitory signalling and simultaneously delivers CD137‐mediated T cell costimulation. The fusion protein was produced with high purity and demonstrated specific binding to PD‐L1‐expressing tumour cells and CD137‐positive T cells. The hPD1‐CD137L retained a stable multimeric structure under acidic conditions and during prolonged storage, supporting its suitability for systemic administration and activity within the tumour microenvironment. Functionally, hPD1‐CD137L enhanced T cell activation, as evidenced by increased NF‐κB signalling and activation marker expression, and promoted robust tumour cell cytolysis in both 2D and 3D co‐culture systems. Anti‐tumour activity was observed across multiple tumour models with varying PD‐L1 expression, including nasopharyngeal carcinoma (NPC), rhabdomyosarcoma, lung carcinoma and patient‐derived colorectal cancer organoids. Notably, hPD1‐CD137L enhanced cytolysis of C666 NPC cells by patient‐derived tumour‐infiltrating lymphocytes at low effector‐to‐target ratios, and was more potent than a combination of an anti‐PD‐1 antibody and a CD137 agonist. In vivo, PBMC‐humanised NSG mice tolerated hPD1‐CD137L without significant weight loss, systemic inflammation or survival impact. Subsequent efficacy study in PBMC‐humanised, Rd18 rhabdomyosarcoma‐engrafted or C666 nasopharyngeal carcinoma‐engrafted NSG mice showed tumour growth suppression without overt toxicity. This study validates a human PD1‐CD137L fusion protein as a potent drug candidate for cancer immunotherapy.
SN - 0019-2805
SN - 1365-2567
ER -