Recombinant Bacillus Calmette-Guérin Technologies in Immunotherapy

Recombinant Bacillus Calmette-Guérin (rBCG) technologies harness the century-old live attenuated Mycobacterium bovis BCG backbone and augment it through genetic engineering to express heterologous antigens, immunomodulatory molecules or novel adjuvants. By introducing genes encoding pathogen-specific proteins or cytokine-like factors, rBCG strains can direct the host immune response towards desired pathways, notably enhancing Th1-type cellular immunity critical for intracellular pathogens and certain cancers. Advances in vector design, codon optimisation and integrative plasmid systems have improved antigen expression stability and reduced reliance on antibiotic markers. Production innovations such as fed-batch cultivation and pH-stat controls facilitate standardised yields for clinical grade preparations. Beyond tuberculosis, rBCG platforms are being explored as dual vaccines against viral threats, as prime agents in heterologous prime-boost regimens and as intravesical immunotherapeutics in bladder cancer. Collectively, these developments underscore the global significance of rBCG as a versatile, low-cost vaccine and immunotherapy vector with broad applications in infectious disease control and oncology.

Research from Nature Portfolio

In efforts to enhance protective efficacy against Mycobacterium tuberculosis, a recombinant BCG strain expressing low levels of the non-toxic LTAK63 adjuvant demonstrated markedly improved pulmonary immunity. Immunised mice exhibited elevated Th1 cytokines and IL-17 in lung tissues and achieved a two to three log reduction in bacterial burden upon high-dose challenge, while histopathology revealed mitigated inflammation and a subsequent regulatory response that constrained tissue damage. This dual-phase response suggests a balanced immunomodulation capable of robust pathogen clearance without excessive pathology. Another seminal study introduced a temperature-sensitive Mycobacterium paragordonae derivative as an alternative live vaccine candidate. Compared with standard BCG, this strain elicited stronger dendritic-cell maturation, a shift towards Th1 cytokine profiles and enhanced cytotoxic T-cell responses, resulting in superior protection against both M. tuberculosis and M. abscessus challenges in murine models. These foundational studies illustrate the potential of recombinant mycobacterial platforms to fine-tune host immunity and inform next-generation vaccine design.

Recombinant Bacillus Calmette-Guérin Technologies in Immunotherapy publication trend

The graph below shows the total number of articles in recombinant bacillus calmette-guérin technologies in immunotherapy across all publications each year (not limited to Nature Index journals).

Technical terms

Recombinant Bacillus Calmette-Guérin (rBCG): A genetically modified live attenuated Mycobacterium bovis BCG strain engineered to express non-native antigens or immune modulators.

Adjuvant: A substance co-delivered with vaccine antigens to enhance and direct the host immune response.

Th1 immune response: A cell-mediated pathway characterised by interferon-γ production and macrophage activation, essential for defence against intracellular pathogens.

Cytokine: A secreted protein messenger that regulates the intensity and duration of immune reactions.

Lyophilisation: A freeze-drying process used to stabilise biological products by removing water under low temperature and pressure, facilitating storage and transport.

References

1. Comparison Between Simple Batch and Fed-Batch Bioreactor Cultivation of Recombinant BCG. Pharmaceutics (2024).
2. Engineering a dual vaccine against COVID-19 and tuberculosis. Frontiers in Cellular and Infection Microbiology (2023).
3. Next-Generation Vaccines Based on Bacille Calmette–Guérin. Frontiers in Immunology (2018).
4. In vitro Evidence of Human Immune Responsiveness Shows the Improved Potential of a Recombinant BCG Strain for Bladder Cancer Treatment. Frontiers in Immunology (2019).
5. Recombinant BCG Expressing LTAK63 Adjuvant induces Superior Protection against Mycobacterium tuberculosis. Scientific Reports (2017).
6. A temperature sensitive Mycobacterium paragordonae induces enhanced protective immune responses against mycobacterial infections in the mouse model. Scientific Reports (2017).