TARGETING BACTERIAL BIOFILMS-MEDIATED DYSREGULATION OF IMMUNE CHECKPOINTS: A NEW DIMENSION FOR ANTI-PATHOGENIC IMMUNOTHERAPY
DOI:
https://doi.org/10.36320/ajb/v18.i2.24991Keywords:
Biofilm, PD-1/PD-L1, Immune checkpoint inhibitors, Antibiotics, chronic infection, cytokines, Staphylococcus aureus, Pseudomonas aeruginosaAbstract
Bacterial infections associated with biofilms continue to be significant clinical problem due to their antibiotic resistance and immunosuppressive capabilities. The recent evidence indicates that the immune checkpoint signaling (PD-1/PD-L1) is involved in the immune impairment in chronic biofilm infections. The study examined the importance of such pathways and whether immune checkpoint inhibitors (ICIs) can be used with antibiotics to enhance the ability to eliminate bacteria and rebuild immune functions. Biofilms of Staphylococcus aureus and Pseudomonas aeruginosa in vitro also were developed and co-cultured with human peripheral blood mononuclear cells (PBMCs). They compared the following four groups: control, ciprofloxacin, antibodies against anti-PD-1/PD-L1 alone and the combination of these two types of antibodies. The crystal violet staining and the confocal microscopy method were used as methods of assessing biofilm biomass, whereas colony-forming unit (CFU) counts were used as the method of measuring viable bacteria. The flow cytometry analysis of PD-1/PD-L1 on T cells was complemented by the analysis of gene expression by qRT-PCR and the level of cytokines by ELISA. Results: Combination therapy yielded the best effect as it decreased biofilm biomass up to 70% in comparison with 35-45% reductions using one of the treatments. Bacterial viability in combination group was also much worse compared to monotherapy groups. Also, the PD-1/PD-L1 on the CD4+ and CD8+ T cells were significantly lowered, as well as TNF-a and IFN-g were elevated and IL-10 was lowered, with a shift up the pro-inflammatory immune response. These results indicate that immune checkpoint blockade is potentially able to augment antibiotic effects against infections caused by biofilms by reversing immunosuppression caused by infection. This integrated approach could be an effective treatment option against chronic and antimicrobial-resistant bacterial infections, but additional in vivo research is necessary to determine the effectiveness of the approach, the optimal dose level, and safety.
Downloads
References
1. Kesthely, C. A., Rogers, R. R., El Hafi, B., Jean-Pierre, F., & O’Toole, G. A. (2023). Transcriptional profiling and genetic analysis of a cystic fibrosis airway-relevant model shows asymmetric responses to growth in a polymicrobial community. Microbiology Spectrum, 11(5), e02201-23. https://doi.org/https://doi.org/10.1128/spectrum.02201-23
2. Yu, X., Zhang, Y., Yao, Y., Cho, W. C., & Shang, A. (2026). Biofilm-mediated immune dysregulation in chronic pulmonary diseases: Mechanisms and clinical implications. Frontiers in Microbiology, 16. https://doi.org/https://doi.org/10.3389/fmicb.2025.1736384
3. Gao, Q., Teng, Y., Zhu, L., Zhang, W., & Li, Z. (2025). The immunosuppressive mechanisms induced by sepsis and the corresponding treatment strategies. Frontiers in Immunology, 16. https://doi.org/https://doi.org/10.3389/fimmu.2025.1643194
4. Hemati, S., & Mohsenipour, Z. (2026). Immune exhaustion in bacterial infections: Mechanisms, consequences, and therapeutic implications. The Brazilian Journal of Infectious Diseases, 30(3), 105809. https://doi.org/https://doi.org/10.1016/j.bjid.2026.105809
5. Kesthely Christopher A., Rogers Rendi R., El Hafi Bassam, Jean-Pierre Fabrice, & O’Toole George A. (2023). Transcriptional profiling and genetic analysis of a cystic fibrosis airway-relevant model shows asymmetric responses to growth in a polymicrobial community. Microbiology Spectrum, 11(5), e02201-23. https://doi.org/https://doi.org/10.1128/spectrum.02201-23
6. Chen, Y., Guo, D., Zhu, C., Ren, S., Sun, C., Wang, Y., & Wang, J. (2023). The implication of targeting PD-1:PD-L1 pathway in treating sepsis through immunostimulatory and anti-inflammatory pathways. Frontiers in Immunology, 14. https://doi.org/https://doi.org/10.3389/fimmu.2023.1323797
7. Chen, X., Feng, L., Huang, Y., Wu, Y., & Xie, N. (2023). Mechanisms and Strategies to Overcome PD-1/PD-L1 Blockade Resistance in Triple-Negative Breast Cancer. Cancers, 15(1), 104. https://doi.org/https://doi.org/10.3390/cancers15010104
8. Herb, M., & Schramm, M. (2021). Functions of ROS in Macrophages and Antimicrobial Immunity. Antioxidants, 10(2), 313. https://doi.org/https://doi.org/10.3390/antiox10020313
9. Lister, J. L., & Horswill, A. R. (2014). Staphylococcus aureus biofilms: Recent developments in biofilm dispersal. Frontiers in Cellular and Infection Microbiology, 4. https://doi.org/https://doi.org/10.3389/fcimb.2014.00178
10. Hotchkiss, R. S., Monneret, G., & Payen, D. (2013). Sepsis-induced immunosuppression: From cellular dysfunctions to immunotherapy. Nature Reviews Immunology, 13(12), 862–874. https://doi.org/https://doi.org/10.1038/nri3552
11. Zhang, T., Yu-Jing, L., & Ma, T. (2023). Role of regulation of PD-1 and PD-L1 expression in sepsis. Frontiers in Immunology, 14. https://doi.org/https://doi.org/10.3389/fimmu.2023.1029438
12. Ismail, H., & Hassan, A. (2026). Immune Checkpoint Inhibitors: Efficacy, safety, and biomarkers—A systematic review. Frontiers in Oncology, 16. https://doi.org/https://doi.org/10.3389/fonc.2026.1789760
13. Robey, R. C., Logue, C., Caird, C. A., Hansel, J., Hellyer, T. P., Simpson, J., Dark, P., Mathioudakis, A. G., & Felton, T. (2024). Immunomodulatory drugs in sepsis: A systematic review and meta-analysis. Anaesthesia, 79(8), 869–879. https://doi.org/https://doi.org/10.1111/anae.16263
14. Wu, Y., Wang, L., Li, Y., Cao, Y., Wang, M., Deng, Z., & Kang, H. (2024). Immunotherapy in the context of sepsis-induced immunological dysregulation. Frontiers in Immunology, 15. https://doi.org/https://doi.org/10.3389/fimmu.2024.1391395
15. Hao, E., Li, Y., Guo, B., Yang, X., Lu, P., & Qiao, H. (2022). Key Residues Affecting Binding Affinity of Sirex noctilio Fabricius Odorant-Binding Protein (SnocOBP9) to Aggregation Pheromone. International Journal of Molecular Sciences, 23(15), 8456. https://doi.org/https://doi.org/10.3390/ijms23158456
16. Rahimi, M. H., Conti, F., Llitjos, J.-F., Fleurie, A., Cerro, V., Venet, F., Lukaszewicz, A.-C., & Monneret, G. (2023). Monocyte HLA-DR expression as an enrollment biomarker in sepsis clinical trials: Evaluation of two sampling tubes and definition of respective clinical thresholds. Cytometry Part B: Clinical Cytometry, 104(6), 468–470. https://doi.org/https://doi.org/10.1002/cyto.b.22133
17. Hanke, M. L., Heim, C. E., Angle, A., Sanderson, S. D., & Kielian, T. (2013). Targeting macrophage activation for the prevention and treatment of Staphylococcus aureus biofilm infections. The Journal of Immunology, 190(5), 2159–2168. https://doi.org/https://doi.org/10.4049/jimmunol.1202348
18. Lade, H., Park, J. H., Chung, S. H., Kim, I. H., Kim, J.-M., Joo, H.-S., & Kim, J.-S. (2019). Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media. Journal of Clinical Medicine, 8(11), 1853. https://doi.org/https://doi.org/10.3390/jcm8111853
19. Mirzaei, R., Sabokroo, N., Ahmadyousefi, Y., Motamedi, H., & Karampoor, S. (2022). Immunometabolism in biofilm infection: Lessons from cancer. Molecular Medicine, 28(1), 10. https://doi.org/https://doi.org/10.1186/s10020-022-00435-2
20. Charpentier, E., Doudet, L., Allart-Simon, I., Colin, M., Gangloff, S. C., Gérard, S., & Reffuveille, F. (2021). Synergy between Indoloquinolines and Ciprofloxacin: An Antibiofilm Strategy against Pseudomonas aeruginosa. Antibiotics, 10(10), 1205. https://doi.org/https://doi.org/10.3390/antibiotics10101205
21. Soares, A., Roussel, V., Pestel-Caron, M., Barreau, M., Caron, F., Bouffartigues, E., Chevalier, S., & Etienne, M. (2019). Understanding Ciprofloxacin Failure in Pseudomonas aeruginosa Biofilm: Persister Cells Survive Matrix Disruption. Frontiers in Microbiology, 10. https://doi.org/https://doi.org/10.3389/fmicb.2019.02603
22. Lebeaux, D., Chauhan, A., Rendueles, O., & Beloin, C. (2013). From in vitro to in vivo Models of Bacterial Biofilm-Related Infections. Pathogens, 2(2), 288–356. https://doi.org/https://doi.org/10.3390/pathogens2020288
23. Zhang, H., Dai, Z., Wu, W., Wang, Z., Zhang, N., Zhang, L., Zeng, W.-J., Liu, Z., & Cheng, Q. (2021). Regulatory mechanisms of immune checkpoints PD-L1 and CTLA-4 in cancer. Journal of Experimental & Clinical Cancer Research, 40(1), 184. https://doi.org/https://doi.org/10.1186/s13046-021-01987-7
24. Henriksen, N. L., Jensen, P. Ø., & Jensen, L. K. (2025). Immune checkpoint blockade in experimental bacterial infections. Journal of Infection, 90(2), 106391. https://doi.org/https://doi.org/10.1016/j.jinf.2024.106391
25. Burns, E. A., Gee, K., Kieser, R. B., Xu, J., Zhang, Y., Crenshaw, A., Muhsen, I. N., Mylavarapu, C., Esmail, A., Shah, S., Umoru, G., Sun, K., Guerrero, C., Gong, Z., Heyne, K., Singh, M., Zhang, J., Bernicker, E. H., & Abdelrahim, M. (2023). Impact of Infections in Patients Receiving Pembrolizumab-Based Therapies for Non-Small Cell Lung Cancer. Cancers, 15(1), 81. https://doi.org/https://doi.org/10.3390/cancers15010081
26. Karam, J.-D., Noel, N., Voisin, A.-L., Lanoy, E., Michot, J.-M., & Lambotte, O. (2020). Infectious complications in patients treated with immune checkpoint inhibitors. European Journal of Cancer, 141, 137–142. https://doi.org/https://doi.org/10.1016/j.ejca.2020.09.025
27. Ross, J. A., Komoda, K., Pal, S., Dickter, J., Salgia, R., & Dadwal, S. (2022). Infectious complications of immune checkpoint inhibitors in solid organ malignancies. Cancer Medicine, 11(1), 21–27. https://doi.org/https://doi.org/10.1002/cam4.4393
28. Grabska, S., Grabski, H., Makunts, T., & Abagyan, R. (2024). Co-Occurring Infections in Cancer Patients Treated with Checkpoint Inhibitors Significantly Increase the Risk of Immune-Related Adverse Events. Cancers, 16(16), 2820. https://doi.org/https://doi.org/10.3390/cancers16162820
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Zahraa Mushreq Hadi Khorsheed
This work is licensed under a Creative Commons Attribution 4.0 International License.
which allows users to copy, create extracts, abstracts, and new works from the Article, alter and revise the Article, and make commercial use of the Article (including reuse and/or resale of the Article by commercial entities), provided the user gives appropriate credit (with a link to the formal publication through the relevant DOI), provides a link to the license, indicates if changes were made and the licensor is not represented as endorsing the use made of the work.
