# Pseudomonas aeruginosa enhances anti-PD-1 efficacy in colorectal cancer by activating cytotoxic CD8+ T cells

## TL;DR

This study shows that Pseudomonas aeruginosa can boost the effectiveness of a cancer treatment by activating immune cells in colorectal cancer patients.

## Contribution

The study identifies Pseudomonas aeruginosa and its component PA-MSHA as a novel agent to enhance anti-PD-1 therapy in CRC.

## Key findings

- Pseudomonas aeruginosa is highly abundant in fecal flora of mice responding to αPD-1 treatment.
- PA-MSHA combined with αPD-1 activates CD8+ T cells to improve CRC treatment outcomes.
- PA-MSHA is proposed as a potential clinical therapeutic option for CRC when combined with αPD-1.

## Abstract

Immune checkpoint therapy for colorectal cancer (CRC) has been found to be unsatisfactory for clinical treatment. Fecal microbiota transplantation (FMT) has been shown to remodel the intestinal flora, which may improve the therapeutic effect of αPD-1. Further exploration of key genera that can sensitize cells to αPD-1 for CRC treatment and preliminary exploration of immunological mechanisms may provide effective guidance for the clinical treatment of CRC.

In this study, 16S rRNA gene sequencing was analyzed in the fecal flora of both responders and no-responders to αPD-1 treatment, and the therapeutic effect was experimentally verified.

Pseudomonas aeruginosa was found to be highly abundant in the fecal flora of treated mice, and Pseudomonas aeruginosa mannose-sensitive hemagglutinin (PA-MSHA) in combination with αPD-1 was effective in the treatment of CRC through the induction of CD8+ T-cell immunological effects.

The clinical drug PA-MSHA can be used in combination with αPD-1 for the treatment of CRC as a potential clinical therapeutic option.