Noshin Daula^1*, Saher Waseem², Ahmad³, and Ayesha⁴

¹Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, UK
²Department of Medicine, Karachi Medical and Dental College, UK
³Emergency Medicine, Khyber Medical Centre, Pakistan
⁴Internal Medicine, Jinnah Sindh Medical University, Pakistan

*Corresponding Author: Noshin Daula, Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, UK.

Received: July 08, 2026; Published: August 31, 2026

Abstract

Listeria monocytogenes has emerged as a promising bacterial vector for cancer immunotherapy because of its unique intracellular life cycle and ability to induce robust innate and adaptive immune responses. Unlike many other bacterial vectors, L. monocytogenes efficiently escapes the phagolysosome, allowing tumour-associated antigens to be processed through the major histocompatibility complex (MHC) class I pathway and eliciting potent CD8⁺ cytotoxic T-cell responses. These characteristics have led to the development of several recombinant and attenuated Listeria-based vaccines targeting a range of malignancies, including cervical, prostate, osteosarcoma and HER2-positive cancers. This review discusses the principal virulence factors of L. monocytogenes, including listeriolysin O (LLO), internalins, phospholipases, ActA and PrfA, and explains how these factors have been engineered to produce safe and effective immunotherapeutic vectors. In addition, the review summarises the mechanisms underlying host immune activation, strategies used to attenuate bacterial virulence while preserving immunogenicity, and the outcomes of major preclinical and clinical studies. Finally, current challenges, safety considerations and future directions of Listeria-based cancer immunotherapy are discussed. Although several hurdles remain before widespread clinical implementation, recombinant L. monocytogenes represents a highly promising platform for next-generation cancer immunotherapy owing to its ability to stimulate durable cell-mediated antitumour immunity.

Keywords: Listeria monocytogenes, Cancer Immunotherapy; Bacterial Vaccine; Listeriolysin O; Virulence Factors; Attenuated Vaccines; Tumour Immunology; Recombinant Bacterial Vectors

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Citation

Citation: Noshin Daula., et al. “How Virulence of Listeria monocytogenes Can be Harnessed to Develop An Immunotherapeutic Agent". Acta Scientific Microbiology 9.9 (2026): 23-30.

Copyright

Copyright: © 2026 Noshin Daula., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.