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Updated: Oct 3, 2025
Polarization of M1 and M2 Human Monocyte-Derived Cells and Analysis with Flow Cytometry upon Mycobacterium tuberculosis Infection
Published on: September 18, 2020
Comparison of Cytokines Expression from Human Monocyte-Derived Macrophages Infected with Different Species of
Abhilasha Madhvi1,2, Hridesh Mishra1,2, Novel N Chegou1
1DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, and Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
Abstract:
Cytokines have an important role in mounting effective host immune response against mycobacteria. Latent tuberculosis infection (LTBI) is an indication of containment of mycobacteria by the host immune response, whereas active TB is an indication of a failure of the immune response to contain Mycobacterium tuberculosis. The dynamics of this host-immune response during in vitro infection experiment is believed to be indicative of behavior in the LTBI and active-TB cases. This relationship is, however, not fully elucidated. We investigated the cytokines expression at mRNA and protein level across 2 different protocols, that is, an in vitro protocol comparing human monocyte-derived macrophages (hMDMs; n = 12) infected with different species of mycobacteria, and a clinical protocol comparing TB-Antigen-Nil specimens from LTBI (n = 12) and active-TB (n = 12) cases. We found that in vitro infection of hMDMs with Mycobacterium bovis Bacillus Calmette-Guérin (BCG) and M. tuberculosis R179 showed increased colony-forming units at all time points postinfection. M. bovis BCG-infected hMDMs demonstrated higher levels of 5 cytokines [interferon (IFN)-γ, interleukin (IL)-6, IL-1β, IL-12p40, and IL-12p70] at different intervals compared to M. tuberculosis R179. Compared to LTBI, active-TB cases had higher mRNA expression of IFN-α, IL-6, and IL-8, and lower expression of IFN-γ, IL-1α, IL-1β, IL-4, and tumor necrosis factor-α. Overall, we observed differential host responses at mRNA and protein levels during experimentally controlled in vitro infection, but no prominent differences were observed in the clinical protocol. Therefore, the result of the in vitro experiment model of cytokine response against mycobacteria should be interpreted cautiously when relating to LTBI and active-TB.
