A defined commensal consortium elicits CD8 T cells and anti-cancer immunity

Area of Science:

• Microbiome research
• Immunology
• Gastroenterology

Background:

• The gut microbiota is a key therapeutic target for various diseases.
• Limited knowledge exists on commensal strains for manipulating host physiology.

Purpose of the Study:

• To isolate and characterize a bacterial consortium for immune modulation.
• To evaluate its therapeutic potential in infection and cancer models.

Main Methods:

• Isolation of an 11-bacterial strain consortium from human donor feces.
• Assessment of interferon-gamma (IFN-γ) producing CD8 T cell induction in the intestine.
• Evaluation of host resistance against Listeria monocytogenes infection in mice.
• Analysis of therapeutic efficacy of immune checkpoint inhibitors in syngeneic tumor models.

Main Results:

• The 11-strain consortium robustly induces IFN-γ-producing CD8 T cells without inflammation.
• Immune induction is dependent on CD103+ dendritic cells and MHC class Ia molecules.
• Colonization enhances resistance to Listeria monocytogenes infection.
• The consortium improves the efficacy of immune checkpoint inhibitors in tumor models.

Conclusions:

• This novel 11-bacterial strain consortium represents a promising biotherapeutic strategy.
• The strains, rare in the human microbiome, offer broad potential for immune manipulation.
• The findings highlight the gut microbiota's role in host defense and cancer therapy.