Targeting NKG2DLs with an ADCC enhanced fusion protein for induction of NK cell reactivity against ovarian cancer

Sep 22, 2026

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Ligands for the activating immune receptor NKG2D (NKG2DLs) are commonly overexpressed on malignant cells and largely absent from healthy tissues, including in ovarian cancer—a highly lethal disease often marked by chemoresistance and relapse. Prior ovarian cancer therapies with monoclonal antibodies have not delivered strong benefits. This work develops an Fc-optimized NKG2D-Ig fusion protein to exploit tumor-associated NKG2DL expression and engage NK cells through ADCC.

LanguageEnglish

CategoryHealthcare

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Pages15

Reading Time38 min

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Abstract

Introduction

Hagelstein etal. Journal of Ovarian Research (2026) 19:59 Journal of Ovarian Research [https://doi.org/10.1186/s13048-025-01962-2](https://doi.org/10.1186/s13048-025-01962-2) RESEARCH Open Access Targeting NKG2DLs with an ADCC enhanced fusion protein for induction of NK cell reactivity against ovarian cancer Ilona Hagelstein1,2,3, Kevin Wang1,2, Annika Hölz1,2, Johanna Blessing1,2 and Martina S. Lutz 1,2,3* Abstract Ligands for the activating immune receptor NKG2D (NKG2DLs) are frequently overexpressed on malignant cells while largely absent in healthy tissues. Elevated expression of various NKG2DLs has been reported in ovarian cancer, one of the most lethal gynecologic malignancies due to chemoresistance and relapse. Despite the advent of monoclonal antibodies (mAbs) in cancer therapy, patients with ovarian cancer have yet to benefit from this treatment modality. Natural killer (NK) cells play a crucial role in the efficacy of antitumor mAbs by mediating antibody-dependent cellular cytotoxicity (ADCC) . Strategies to enhance ADCC often involve Fc region modifications to improve CD16 binding and NK cell activation. The tumor-associated expression of NKG2DLs was exploited by developing an Fc-optimized NKG2D-Ig fusion protein (NKG2D-ADCC) to trigger NK cell ADCC against ovarian cancer cells. The NKG2D-Ig fusion protein with awildtype Fc version (NKG2D-WT) was modified in the Fc part by introducing the S239D/I332E mutations, thereby enhancing the binding affinity to the Fc receptor CD16 . Flow cytometric analysis revealed a diverse range of expression patterns for NKG2DLs across ovarian cancer cell lines. Functionally, NKG2D-ADCC induced stronger NK cell activation than NKG2D-WT, promoting degranulation and secretion of effector molecules, including IFN-γ and granzymes. The unrelated control protein lacked such effects, confirming specificity. Notably, NKG2D-ADCC induced robust NK cell-mediated lysis of ovarian cancer cells in both short-and long-term cytotoxicity assays. Together, these findings demonstrate that the NKG2D-ADCC fusion protein potently enhances NK cell responses against ovarian cancer cells, supporting its promise as a novel immunotherapeutic strategy. Keywords Immunotherapy, NK cells, Fusion protein, NKG2D, NKG2DL, Ovarian cancer *Correspondence: Martina S. Lutz [martina.lutz@med.uni-tuebingen.de](martina.lutz@med.uni-tuebingen.de) 1German Cancer Consortium (DKTK), partner site Tübingen, a partnership between DKFZ and University Hospital Tübingen, Tübingen, Germany 2Department of Internal Medicine, Clinical Collaboration Unit Translational Immunology, University Hospital Tübingen, Tübingen, Germany 3Cluster of Excellence iFIT (EXC 2180)“Image-Guided and Functionally Instructed Tumor Therapies”, University ofTübingen, Tübingen, Germany © The Author(s) 2026. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit [http://creativecommons.org/licenses/by/4.0/](http://creativecommons.org/licenses/by/4.0/.)[.](http://creativecommons.org/licenses/by/4.0/.) Hagelstein et al. Journal of Ovarian Research (2026) 19:59 Introduction The immune system plays a critical role in the recognition and elimination of malignant cells. A pivotal mechanism by which

FAQs

Why are NKG2DLs considered promising targets in ovarian cancer?

NKG2DLs are frequently overexpressed on malignant cells while largely absent in healthy tissues. Elevated NKG2DL expression has been reported in ovarian cancer and can be further induced by chemotherapy and radiotherapy.

What strategy does the study use to enhance NK cell activity?

The study exploits tumor-associated NKG2DL expression by creating an Fc-optimized NKG2D-Ig fusion protein designed to trigger NK cell ADCC against ovarian cancer cells.

How does the Fc-optimized fusion protein improve NK cell responses compared with the wildtype version?

The Fc-optimized variant introduces S239D/I332E mutations to enhance binding affinity to the Fc receptor CD16. It induces stronger NK cell activation, including degranulation and secretion of effector molecules such as IFN-γ and granzymes, and promotes robust tumor cell lysis.

Sep 22, 2026

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