Cubas, R. | bioRxiv Science

bioRxiv2026

Inhibition of integrin αvβ8-mediated TGFβ activation and active-TGFβ blockade promote anti-tumor immunity through distinct biological mechanisms

Transforming Growth Factor {beta} (TGF{beta}) is a potent immunosuppressor and a primary driver of resistance to cancer immunotherapy. While preclinical models have long suggested that TGF{beta} inhibition could synergize with immune checkpoint inhibitors, these effects have proven difficult to replicate in clinical settings. The highly regulated TGF{beta} pathway can be inhibited through various mechanisms, including neutralizing activated ligands or inhibiting upstream activators, such as integrins. Recent structural data demonstrated that integrin v{beta}8 can enable TGF{beta}1/3 signaling without releasing the active cytokines from their Latency-Associated Peptides, suggesting that ligand-blocking antibodies may have limited access to their epitopes. Here, we show that integrin v{beta}8 blockade, while achieving anti-tumor responses similar to those of anti-TGF{beta} antibodies, does so through a distinct mechanism of action. Anti-v{beta}8 is 3 orders of magnitude more potent at inhibiting v{beta}8-mediated TGF{beta} activity than a commonly used antibody against the mature form of the cytokine. Whereas TGF{beta} ligand inhibition has little effect on TGF{beta} signaling in tumor-draining lymph nodes (tdLN) and requires IFN{gamma} for its anti-tumor effects, v{beta}8 blockade strongly inhibits TGF{beta} signaling in tdLN and, in combination with PD-L1 blockade, drives tumor control through an IFN{gamma} -independent mechanism that strictly requires T cell egress from tdLN. Combined v{beta}8 and anti-PD-L1 blockade enhances antigen presentation in dendritic cells (DCs) and, unlike TGF{beta} ligand blockade, improves the efficiency of DC-induced T cell activation in response to cross-presented antigen. These findings suggest that v{beta}8 blockade can disable an immunologically critical source of TGF{beta} signaling that is not addressed by antibodies targeting TGF{beta} ligands, suggesting a promising new approach to TGF{beta} pathway modulation. One Sentence SummaryUnlike ligand-neutralizing antibodies, v{beta}8 blockade suppresses TGF{beta} in tdLN and boosts DC-T cell activation, a differentiated immunotherapy strategy.

immunology↗

bioRxiv2020

Projecting single-cell transcriptomics data onto a reference T cell atlas to interpret immune responses

Single-cell RNA-sequencing (scRNA-seq) has emerged as a revolutionary technology for characterizing the heterogeneity of cell populations. However, robust reference atlases that can be used to systematically interpret cellular states across studies and diseases are currently lacking. Here, we generated the first cross-study T cell atlases for cancer and viral infection and developed a novel algorithm, ProjecTILs, that enables the projection of new scRNA-seq data onto these reference atlases. ProjecTILs accurately predicted the effects of multiple perturbations, including the ablation of immunoregulatory targets controlling T cell differentiation, such as Tox, Ptpn2, miR-155 and Regnase-1, and suggested novel gene programs that were altered in these cells. Moving beyond mouse models, we used ProjecTILs to conduct a meta-analysis of human tumor-infiltrating T lymphocytes (TILs), revealing a remarkable conservation of TIL subtypes between human and mouse and across cancer types. Clonotype analysis supported a model in which rare human tumor-specific effector-memory (EM)-like CD8 TILs that resemble blood-circulating EM cells, differentiate into proliferative terminal exhausted/dysfunctional effector TILs through a progenitor subtype that upregulates the exhaustion master regulator TOX. Our novel computational method allows exploring the effect of human and murine T cell perturbations (e.g. as the result of therapy or genetic engineering) in terms of reference cellular states, altered genetic programs and clonotype structure, revealing mechanisms of action behind immunotherapies and opening opportunities for their improvement.

bioinformatics↗