Microbiome

Organic chemistry

Inulin

Gut flora

Bioinformatics

Biology

Microbiology

Chemistry

Immunology

In situ

Immunity

Immune modulation

Gut microbiome

Biochemistry

Immune system

Pharmacology

Nature Biomedical Engineering

The performance of immune-checkpoint inhibitors, which benefit only a subset of patients and can cause serious immune-related adverse events, underscores the need for strategies that induce T-cell immunity with minimal toxicity. The gut microbiota has been implicated in the outcomes of patients following cancer immunotherapy, yet manipulating the gut microbiome to achieve systemic antitumour immunity is challenging. Here we show in multiple murine tumour models that inulin—a widely consumed dietary fibre—formulated as a ‘colon-retentive’ orally administered gel can effectively modulate the gut microbiome in situ, induce systemic memory-T-cell responses and amplify the antitumour activity of the checkpoint inhibitor anti-programmed cell death protein-1 (α-PD-1). Orally delivered inulin-gel treatments increased the relative abundances of key commensal microorganisms and their short-chain-fatty-acid metabolites, and led to enhanced recall responses for interferon-γ+CD8+ T cells as well as to the establishment of stem-like T-cell factor-1+PD-1+CD8+ T cells within the tumour microenvironment. Gels for the in situ modulation of the gut microbiome may be applicable more broadly to treat pathologies associated with a dysregulated gut microbiome. An orally administered gel that is retained in the colon modulates the gut microbiome of mice with murine tumours, inducing systemic memory-T-cell responses and amplifying the antitumour activity of a checkpoint inhibitor.

Generation of systemic antitumour immunity via the in situ modulation of the gut microbiome by an orally administered inulin gel