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Fusion of Mycoplasma fermentans strain incognitus with T-lymphocytes
G Franzoso1, D S Dimitrov, R Blumenthal
1Laboratory of Mycoplasma, FDA, Bethesda, MD 20892.
Abstract:
The ability of Mycoplasma fermentans (strain incognitus) to fuse with cultured lymphocytes was investigated and the fusion process was characterized. Fusion was measured using an assay to determine lipid mixing based on the dequenching of the fluorescent probe, octadecylrhodamine (R18), that was incorporated into the mycoplasma cells. Fusion of M. fermentans was detected with both CD4+ (Molt 3) and CD4- (12-E1) cells. The amount of fusion induced was relatively low and ranged from 5-10% with either cell culture. When primary peripheral blood lymphocytes were used the fusion yield was somewhat higher, reaching 12% of the cell population. Similar findings were obtained with fluorescent microscopy analysis suggesting that a predetermined, but unidentified subpopulation of cultured lymphocytes, were being fused. The rate of fusion was temperature dependent. Following a short lag period fusion at 37 degrees C was virtually completed in 60 min. The lymphocytes remained intact throughout the fusion process, as determined by the Trypan blue staining procedure. Fusion was almost completely inhibited by anti-M. fermentans antisera and by pretreatment of M. fermentans cells with proteolytic enzymes, suggesting that a surface-exposed proteinaceous component is involved in the fusion process.
Insights
Mycoplasma fermentans can fuse with lymphocytes, a process dependent on temperature and involving a protein component. This fusion, though limited, was observed in both cultured and primary cells.
Area of Science:
- Microbiology
- Cell Biology
- Immunology
Background:
- Mycoplasma fermentans is a bacterium known for its ability to interact with host cells.
- Understanding the mechanisms of microbial-host cell interaction is crucial in infectious disease research.
Purpose of the Study:
- To investigate and characterize the fusion process between Mycoplasma fermentans (strain incognitus) and cultured lymphocytes.
- To identify factors influencing the fusion efficiency and mechanism.
Main Methods:
- Lipid mixing assay using octadecylrhodamine (R18) fluorescent probe to quantify fusion.
- Fluorescent microscopy for visual confirmation of fusion.
- Trypan blue staining to assess lymphocyte integrity.
- Inhibition assays using anti-M. fermentans antisera and proteolytic enzymes.
Main Results:
- Mycoplasma fermentans fused with both CD4+ and CD4- cultured lymphocytes, as well as primary peripheral blood lymphocytes.
- Fusion efficiency ranged from 5-10% with cultured cells and reached 12% with primary lymphocytes.
- Fusion rate was temperature-dependent, completing within 60 minutes at 37°C.
- Fusion was significantly inhibited by anti-M. fermentans antisera and enzymatic treatment, indicating a protein-mediated process.
Conclusions:
- Mycoplasma fermentans can fuse with lymphocytes through a temperature-dependent mechanism.
- A surface-exposed protein on M. fermentans appears to mediate the fusion process.
- The fusion involves a specific subpopulation of lymphocytes and does not compromise lymphocyte integrity.