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Ingestion and survival of Y. pseudotuberculosis in HeLa cells
Abstract:
HeLa cells were infected with Yersinia pseudotuberculosis for 0.5-3 h. Intracellular bacteria could then be demonstrated by three different techniques: viable count, fluorescent-antibody staining and electron microscopy. Most of the bacteria seemed to be viable, since there was a good positive correlation (0.94) between viable and fluorescent bacteria. The bacterial uptake seemed to be mediated by a phagocytic-like procedure. The intracellular bacteria seemed to reside in vacuoles some of which increased in size as a function of time. The kinetics of infection was studied after addition of 10(7) or 10(9) bacteria per cell culture (2 X 10(6) cells). After a lag period of about 30 min there was a linear increase of intracellular bacteria, and this uptake proceeded for 1-2 h until most of the bacteria were ingested or an upper limit of ingested bacteria was reached. The upper limit was calculated to be a mean of 60 per infected cell in the cell culture. More than 90% of the cells could be infected and a reasonable number of the bacteria survive in the cells for at least 3 days, as demonstrated by the viable-count technique. The bacteria-cell system may be used to study, for example, the effect of antibiotics or antibodies on intracellular bacteria and pathogenicity of intracellular diseases.
Insights
Yersinia pseudotuberculosis infects HeLa cells via phagocytosis, with bacteria surviving intracellularly for days. This model aids studying intracellular bacterial infections and treatments.
Area of Science:
- Microbiology
- Cell Biology
- Infectious Diseases
Background:
- Yersinia pseudotuberculosis is a pathogen that can infect host cells.
- Understanding the dynamics of intracellular bacterial infections is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the uptake and survival mechanisms of Yersinia pseudotuberculosis within HeLa cells.
- To establish a model system for studying intracellular bacterial pathogenesis and the efficacy of antimicrobial agents.
Main Methods:
- HeLa cells were infected with Yersinia pseudotuberculosis.
- Intracellular bacteria were quantified using viable counts, fluorescent-antibody staining, and electron microscopy.
- Infection kinetics were analyzed over time following bacterial addition.
Main Results:
- Bacterial uptake occurred through a phagocytic-like process, with bacteria residing in vacuoles.
- A strong correlation (0.94) was observed between viable and fluorescent bacteria, indicating bacterial viability.
- Infection showed a lag phase followed by linear uptake, reaching a maximum of approximately 60 bacteria per cell.
- Over 90% of cells were infected, and bacteria survived intracellularly for at least 3 days.
Conclusions:
- HeLa cells provide a suitable model for studying intracellular Yersinia pseudotuberculosis infections.
- The established model can be utilized to evaluate the impact of antibiotics and antibodies on intracellular bacteria.
- This research contributes to understanding the pathogenicity of intracellular bacterial diseases.