Co-Stimulatory Bispecific Antibodies Induce Enhanced T Cell Activation and Tumor Cell Killing in Breast Cancer Models.

Abstract

Although T cell-recruiting CD3-binding bispecific antibodies (BiMAb) have been proven to be clinically effective for hematologic malignancies, the success of BiMAb targeting solid tumor-associated antigens (TAA) in carcinomas so far remains poor. We reasoned that provision of co-stimulatory BiMAb in combination with αTAA-αCD3 BiMAb would boost T cell activation and proliferative capacity, and thereby facilitate the targeting of weakly or heterogeneously expressed tumor antigens. Various αTAA-αCD3 and αTAA-αCD28 BiMAb in a tetravalent IgG1-Fc based format have been analyzed, targeting multiple breast cancer antigens including HER2, EGFR, CEA, and EpCAM. Moreover, bifunctional fusion proteins of αTAA-tumor necrosis factor ligand (TNFL) superfamily members including 4-1BBL, OX40L, CD70 and TL1A have been tested. The functional activity of BiMAb was assessed using co-cultures of tumor cell lines and purified T cells in monolayer and tumor spheroid models. Only in the presence of tumor cells, αTAA-αCD3 BiMAb activated T cells and induced cytotoxicity in vitro, indicating a strict dependence on cross-linking. Combination treatment of αTAA-αCD3 BiMAb and co-stimulatory αTAA-αCD28 or αTAA-TNFL fusion proteins drastically enhanced T cell activation in terms of proliferation, activation marker expression, cytokine secretion and tumor cytotoxicity. Furthermore, BiMAb providing co-stimulation were shown to reduce the minimally required dose to achieve T cell activation by at least tenfold. Immuno-suppressive effects of TGF-β and IL-10 on T cell activation and memory cell formation could be overcome by co-stimulation. BiMAb-mediated co-stimulation was further augmented by immune checkpoint-inhibiting antibodies. Effective co-stimulation could be achieved by targeting a second breast cancer antigen, or by targeting fibroblast activation protein (FAP) expressed on another target cell. In tumor spheroids derived from pleural effusions of breast cancer patients, co-stimulatory BiMAb were essential for the activation tumor-infiltrating lymphocytes and cytotoxic anti-tumor responses against breast cancer cells. Taken together we showed that co-stimulation significantly potentiated the tumoricidal activity of T cell-activating BiMAb while preserving the dependence on TAA recognition. This approach could provide for a more localized activation of the immune system with higher efficacy and reduced peripheral toxicities.

• Authors: Karsten M Warwas, Marten Meyer, Márcia Gonçalves, Gerhard Moldenhauer, Nadja Bulbuc, Susanne Knabe, Claudia Luckner-Minden, Claudia Ziegelmeier, Claus Peter Heussel, Inka Zörnig, Dirk Jäger, Frank Momburg
• Journal: Frontiers in immunology (Front Immunol) Vol. 12 Pg. 719116 ( 2021) ISSN: 1664-3224 [Electronic] Switzerland
• PMID: 34484225 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 Warwas, Meyer, Gonçalves, Moldenhauer, Bulbuc, Knabe, Luckner-Minden, Ziegelmeier, Heussel, Zörnig, Jäger and Momburg.

Chemical References

• Antibodies, Bispecific
• Antigens, Neoplasm
• Biomarkers
• Cytokines

Topics

• Animals
• Antibodies, Bispecific (immunology, pharmacology)
• Antigens, Neoplasm (immunology)
• Biomarkers
• Breast Neoplasms (immunology, metabolism, pathology)
• Cell Line, Tumor
• Cytokines (metabolism)
• Cytotoxicity, Immunologic (drug effects)
• Disease Models, Animal
• Female
• Humans
• Immunophenotyping
• Lymphocyte Activation (drug effects, immunology)
• Mice
• T-Lymphocytes (drug effects, immunology, metabolism)
• Tumor Microenvironment (genetics, immunology)
• Xenograft Model Antitumor Assays