Bifunctional Immune Modulation in Tumor Microenvironments

Bifunctional immunotherapies combine two distinct modes of action into a single molecule to remodel the tumour microenvironment and overcome resistance to conventional checkpoint blockade. By simultaneously sequestering immunosuppressive cytokines such as transforming growth factor-β (TGF-β) and neutralising immune-checkpoint ligands like programmed death-ligand 1 (PD-L1), these agents release the brakes on effector T cells while reversing stromal and myeloid-mediated suppression. In preclinical models, bifunctional constructs have been shown to expand stem cell-like CD8+ T cell pools, enhance tumour infiltration by cytotoxic lymphocytes and induce a shift from immune-excluded or cold phenotypes towards inflamed, therapy-sensitive ecosystems. Early clinical and translational studies further demonstrate that such dual-target strategies can synergise with radiotherapy, targeted kinase inhibitors and vaccination, offering durable anti-tumour responses across diverse cancer types.

Research from Nature Portfolio

Recent studies have elucidated both the mechanistic rationale and therapeutic benefit of linking TGF-β and PD-L1 blockade in a single agent. In murine carcinoma models, a bifunctional antibody targeting PD-L1 fused to a TGF-β trap enabled the expansion and differentiation of stem cell-like CD8+ T cells, replenishing exhausted populations and yielding an inflamed tumour niche characterised by heightened interferon-γ signalling and enhanced immune-cell motility. Seminal work with antibody–ligand traps demonstrated that dual targeting of CTLA-4 or PD-L1 alongside TGF-β can more effectively reduce regulatory T cell infiltration and stall tumour progression compared with monoclonal checkpoint inhibitors. Complementary mechanistic investigations revealed that TGF-β signalling suppresses CD8+ T cell expression of the chemokine receptor CXCR3, thereby limiting lymphocyte trafficking into tumours; blockade of TGF-β restores CXCR3 levels and facilitates T cell homing, underscoring the importance of bifunctional immunomodulation.

Research from all publishers

A first-in-class phase II trial evaluated a bifunctional fusion protein combining PD-L1 inhibition with TGF-β sequestration alongside a tyrosine kinase inhibitor in advanced biliary tract and pancreatic ductal adenocarcinoma. This regimen achieved objective response rates of 15–28%, disease control in up to 80% of patients and identified an immune-metabolic gene signature predictive of benefit. Preclinical development of a bispecific antibody targeting TGF-β and vascular endothelial growth factor (VEGF) demonstrated potent in vitro blockade of both pathways, leading to superior tumour growth suppression and metastasis prevention when combined with PD-1 blockade in multiple murine models. Single-cell transcriptomics of tumours treated with an anti-TGF-β/PD-L1 bispecific agent uncovered the emergence of immunosuppressive CCR5+ T cell subsets; co-administration of a CCR5 antagonist abrogated this feedback loop, further amplifying antitumour immunity and highlighting a strategy to optimise bispecific antibody efficacy in the clinic.

Bifunctional Immune Modulation in Tumor Microenvironments publication trend

The graph below shows the total number of articles in bifunctional immune modulation in tumor microenvironments across all publications each year (not limited to Nature Index journals).

Technical terms

Bifunctional antibody: A single molecular construct designed to engage two different targets or pathways simultaneously, for example PD-L1 and TGF-β.

Transforming growth factor-β (TGF-β): A multifunctional cytokine that mediates immunosuppression, promotes regulatory T cell differentiation and limits T cell infiltration into tumours.

Programmed death-ligand 1 (PD-L1): An immune-checkpoint ligand expressed by tumour and stromal cells that binds PD-1 on T cells to inhibit their activation.

Tumour microenvironment (TME): The complex milieu of cancer cells, stromal elements, immune populations and extracellular matrix surrounding a tumour that influences response to therapy.

Stem cell-like CD8+ T cell (T_SCL): A progenitor subset of CD8+ T cells with self-renewal capacity that can differentiate into effector cells upon immune-checkpoint blockade.

References

1. Combined PD-L1/TGFβ blockade allows expansion and differentiation of stem cell-like CD8 T cells in immune excluded tumors. Nature Communications (2023).
2. Bifunctional immune checkpoint-targeted antibody-ligand traps that simultaneously disable TGFβ enhance the efficacy of cancer immunotherapy. Nature Communications (2018).
3. TGFβ suppresses CD8+ T cell expression of CXCR3 and tumor trafficking. Nature Communications (2020).
4. Clinical and biomarker analyses of SHR-1701 combined with famitinib in patients with previously treated advanced biliary tract cancer or pancreatic ductal adenocarcinoma: a phase II trial. Signal Transduction and Targeted Therapy (2024).
5. Synergistic efficacy of simultaneous anti-TGF-β/VEGF bispecific antibody and PD-1 blockade in cancer therapy. Journal of Hematology & Oncology (2023).
6. Blockade of CCR5+ T Cell Accumulation in the Tumor Microenvironment Optimizes Anti‐TGF‐β/PD‐L1 Bispecific Antibody. Advanced Science (2024).
7. Simultaneous targeting of TGF-β/PD-L1 synergizes with radiotherapy by reprogramming the tumor microenvironment to overcome immune evasion. Cancer Cell (2021).
8. M7824, a novel bifunctional anti-PD-L1/TGFβ Trap fusion protein, promotes anti-tumor efficacy as monotherapy and in combination with vaccine. OncoImmunology (2018).