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Effects of Mycoplasma fermentans incognitus on differentiation of THP-1 cells
L Reyes1, M K Davidson, L C Thomas
1Division of Comparative Medicine, Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610-0001, USA. lreyes@upha.health.ufl.edu
Abstract:
Mycoplasma fermentans incognitus has been isolated from human tissue in patients both with and without AIDS who died of systemic infection. M. fermentans incognitus and other strains of M. fermentans have been associated with rheumatoid arthritis. While cell extracts of M. fermentans incognitus can induce changes in murine and human cells of the monocytic lineage, little is known about interactions of viable organisms with such cells. Because of the central role of macrophages in chronic inflammation, we examined the effects of M. fermentans incognitus on surface markers and functions of THP-1 cells, a well-characterized human monocytic cell line. This cell line has been used extensively in studies of macrophage differentiation, especially following exposure to phorbol esters. Changes in cell morphology, phagocytosis, rate of cell division, and selected surface markers were evaluated in cultures of THP-1 cells exposed to phorbol myristate acetate (PMA), M. fermentans incognitus, or both. As reported by other investigators, PMA induced THP-1 cells to differentiate into cells resembling tissue macrophages. M. fermentans incognitus only minimally affected changes induced by PMA, slightly increasing the percentage of cells positive for FCgammaRI and major histocompatibility complex (MHC) class II antigens. M. fermentans incognitus alone induced an incomplete arrest in the cell cycle at G0 phase, increased phagocytic ability, and enhanced expression of FCgammaRI, CR3, CR4, and MHC class II antigens.
Insights
Mycoplasma fermentans incognitus, a bacterium linked to rheumatoid arthritis, was studied for its effects on human monocytic cells. The organism alone prompted cell cycle arrest and enhanced immune marker expression, indicating immune modulation potential.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Mycoplasma fermentans incognitus is found in human tissues and associated with rheumatoid arthritis.
- While M. fermentans incognitus extracts affect monocytic cells, interactions with viable organisms are poorly understood.
- Macrophages play a key role in chronic inflammation.
Purpose of the Study:
- To investigate the effects of viable Mycoplasma fermentans incognitus on THP-1 cells, a human monocytic cell line.
- To analyze changes in surface markers and cellular functions upon exposure to M. fermentans incognitus.
Main Methods:
- THP-1 cells were cultured and exposed to phorbol myristate acetate (PMA), M. fermentans incognitus, or both.
- Evaluated changes in cell morphology, phagocytosis, cell division rate, and expression of surface markers (FCgammaRI, MHC class II, CR3, CR4).
Main Results:
- PMA induced THP-1 cell differentiation into macrophage-like cells.
- M. fermentans incognitus alone caused incomplete G0 cell cycle arrest, increased phagocytosis, and enhanced FCgammaRI, CR3, CR4, and MHC class II expression.
- M. fermentans incognitus minimally altered PMA-induced differentiation, slightly increasing FCgammaRI and MHC class II positivity.
Conclusions:
- Viable Mycoplasma fermentans incognitus significantly impacts monocytic cell functions and surface marker expression.
- The bacterium induces immune-related changes in macrophages, suggesting a role in inflammatory processes.
- Further research is warranted to elucidate the mechanisms of M. fermentans incognitus-induced immune modulation.