Tumor-specific antibodies elicited by engineered bacteria promote bladder cancer immunotherapy in preclinical mouse models.

Authors

Mathieu Rouanne, Noah Chen, Dylan L Mariuzza, Zaofeng Yang, Fangda Li, Kenia de Los Santos-Alexis, Thomas M Savage, Rosa L Vincent, Cathy L Mendelsohn, Tal Danino, Nicholas Arpaia

Published in

Science translational medicine. Volume 18. Issue 859. Pages eadv7600. Jul 22, 2026. Epub Jul 22, 2026.

Abstract

The intratumoral microbiome has recently emerged as a potential hallmark of cancer, with implications for response or resistance to therapy. Bacteria can either promote or inhibit cancer growth. However, intratumoral bacteria can also be engineered using synthetic biology to remodel the tumor microenvironment. Here, we engineered the probiotic bacterium Escherichia coli Nissle 1917 (EcN) to express the human chemokine CXCL13 (C-X-C motif chemokine ligand 13), a critical component of germinal center (GC) formation. Antibody affinity maturation and class switching are fundamental aspects of adaptive immune response. Both occur primarily in the GCs of secondary lymphoid organs for defense against pathogens. Immune checkpoint blockade (ICB) efficacy is primarily driven by T cells; however, recent studies in mice and humans have shown that humoral immune responses act as critical partners for ICB-mediated antitumor activity. Using orthotopic models of bladder cancer, intravesically delivered engineered CXCL13-expressing EcN colonized bladder tumors and elicited GC responses in bladder tumor-draining lymph nodes after intravesical delivery. When combined with programmed cell death protein 1 (PD-1) blockade, engineered EcN improved antitumor activity in two aggressive, fast-growing, and immunologically cold orthotopic mouse models of bladder cancer. Mechanistically, this antitumor effect was dependent on the presence of CD8⁺ T cells and CD4⁺ T follicular helper cells; combination therapy increased tumor-specific antibody responses and promoted long-term survival and protective immunity upon tumor rechallenge. Thus, we demonstrate that synthetically engineered CXCL13-expressing EcN can enhance the efficacy of PD-1 checkpoint blockade immunotherapy by amplifying tumor-specific humoral immunity.

PMID:
42485436
Bibliographic data and abstract were imported from PubMed on 23 Jul 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.