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Updated: Apr 16, 2026
Polarization of M1 and M2 Human Monocyte-Derived Cells and Analysis with Flow Cytometry upon Mycobacterium tuberculosis Infection
Published on: September 18, 2020
Infection of human neutrophils to study virulence properties of Mycobacterium tuberculosis
Tobias Dallenga1, Björn Corleis, Ulrich E Schaible
1Cellular Microbiology, Priority Area Infections, Research Center Borstel, Parkallee 1-40, 23845, Borstel, Germany.
Abstract:
Polymorphonuclear neutrophils (PMN) are professional phagocytes and the first line of defense against invading microbes. Upon infection with Mycobacterium tuberculosis, PMN are attracted to the site of infection along an interleukin 8 gradient. In patients with active tuberculosis, PMN comprise the predominant population in the lung and carry the main mycobacterial load suggesting a minor role for PMN in protective host defense against M. tuberculosis but rather in pathology. Therefore, better understanding of PMN biology in tuberculosis is of pivotal importance to develop novel immune modulating measures and host directed therapies. Virulent M. tuberculosis escape the otherwise microbicidal armamentarium of PMNs by inducing necrotic cell death through the PMN's own reactive oxygen species. Studying the interactions between PMN and different M. tuberculosis strains, and virulence factors thereof, is vital to comprehend tuberculosis pathogenesis. Working with PMN is challenging as these cells are non-adherent, motile and-with a half-life of 6-12 h in vitro-rather short-lived. Here, we provide an isolation and infection protocol that is tailored to study mycobacterial infection in human PMN regarding the intracellular fate of mycobacteria and host cell responses, such as cell death and release of microbicidal effectors.
Insights
Polymorphonuclear neutrophils (PMN) play a complex role in tuberculosis, potentially contributing to pathology rather than protection. This study presents a new protocol to investigate PMN interactions with Mycobacterium tuberculosis.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Polymorphonuclear neutrophils (PMN) are key immune cells, crucial in combating microbial infections.
- In tuberculosis, PMN accumulate at infection sites, carrying a significant Mycobacterium tuberculosis burden, suggesting a role in pathogenesis.
- Understanding PMN-M. tuberculosis interactions is vital for developing host-directed therapies.
Purpose of the Study:
- To develop and validate a protocol for studying human PMN responses to M. tuberculosis infection.
- To investigate the intracellular fate of M. tuberculosis within PMN.
- To analyze host cell responses, including cell death and effector release.
Main Methods:
- Isolation of human PMN.
- Infection of PMN with M. tuberculosis strains.
- Analysis of intracellular mycobacterial fate and host cell responses (cell death, effector release).
Main Results:
- The protocol allows for the study of M. tuberculosis infection in human PMN.
- It enables the assessment of intracellular mycobacterial survival and host cell responses.
- This method addresses the challenges of working with short-lived, non-adherent PMN.
Conclusions:
- The developed protocol is crucial for understanding PMN-M. tuberculosis interactions.
- It facilitates research into PMN's role in tuberculosis pathogenesis and potential therapeutic strategies.
- This work provides a foundation for novel immune-modulating treatments for tuberculosis.
